The opinion
TERRY, Associate Judge,
dissenting:
The majority bases its affirmance of appellant’s conviction on the premise that our decision in Graves v. United States, 515 A.2d 1136 (D.C.1986), improperly ignored controlling precedent in Ford v. United States, 498 A.2d 1135 (D.C.1985), so that Graves need not and should not be followed. I cannot accept that premise. Graves did not ignore, and is not inconsistent with, Ford , for the simple reason that the issue presented in Graves was not presented in Ford (as the Graves court made crystal-clear). I would therefore hold that Graves — not Ford — controls this case, and that appellant’s conviction must be reversed because the evidence was insufficient to sustain it. In addition, I believe that the expert testimony was erroneously admitted and that this error is a separate and independent ground for reversal. Accordingly, I dissent.
I
As I read the Ford opinion, and as I recall the Ford argument from having been a member of the division that heard it, the entire focus of the sufficiency argument was on whether the officer’s testimony established a solicitation. There was no challenge whatever to the proof of the purpose of the solicitation, and the division did not raise the issue on its own. Such restraint was, of course, entirely proper.
The premise of our adversarial system is that appellate courts do not sit as self-directed boards of legal inquiry and research, but essentially as arbiters of legal questions presented and argued by the parties before them.
Carducci v. Regan, 230 U.S.App.D.C. 80, 86 , 714 F.2d 171, 177 (1983). Had the court in Ford (or any case) reached out and decided an issue that was not raised by the parties, or at least briefed or argued after having been raised by the court sua sponte, the losing party would have had a legitimate grievance.
Thus the Graves court was absolutely right in concluding that it was not bound by Ford because “Ford does not even discuss, let alone purport to decide, the fee issue.” 515 A.2d at 1147 . There is no occasion to invoke the rule of M.A.P. v. Ryan, 285 A.2d 310 (D.C.1971), that one division of the court may not overrule another, for Graves did not overrule, ignore, or otherwise refuse to follow Ford . The majority’s statement here “that the holding of Ford is that the so-called ‘beckoning’ circumstantial evidence is sufficient to establish guilt of soliciting sexual acts or contacts for a fee,” ante at 173 (emphasis added), puts a greater weight on the Ford opinion than it can bear. In this case, like Graves — but unlike Ford — the fee issue is squarely presented. In both this case and Graves there was zero evidence “that appellant solicited ‘sexual acts or contacts with another person in return for a fee.’ ” 515 A.2d at 1148 , quoting from the statutory definition of prostitution in D.C.Code § 22-2701.1 (1986 Supp.). We reversed the conviction in Graves , quite rightly, because of that lack of evidence; we should reverse the conviction in this case for the same reason.
The court noted in Graves that it had “found no case in the District of Columbia, until Ford , which has upheld a conviction [of soliciting for prostitution] without some reference to financial consideration.” 515 A.2d at 1147 (citations omitted). The only logical explanation for this difference between Ford and all the other reported cases, as the Graves court inferred (and as the record in Ford confirmed), is that the issue of “financial consideration” was not raised in Ford . As Graves and many other cases make clear, the statute requires in every case that there be proof of a commercial purpose in the transaction between the putative prostitute and her putative customer; without such proof, the statute almost certainly could not withstand constitutional challenge. See Wood v. United States, 498 A.2d 1140, 1144 (D.C.1985); United States v. Moses, 339 A.2d 46, 51-53 (D.C.1975), cert. denied, 426 U.S. 920 , 96 *175 S.Ct. 2624 , 49 L.Ed.2d 373 (1976). Although it does not matter which party “broaches the commercial nature of the transaction,” there must be evidence of “an understanding ... that a commercial venture was contemplated when the sexual availability was made apparent.” Dinkins v. United States, 374 A.2d 292, 296 (D.C. 1977) (en banc).
The crime of which appellant was convicted has four elements. The government was required to prove that she
(1) invited, enticed, or persuaded (or addressed for the purpose of inviting, enticing, or persuading) (2) a person age 16 or over (3) for the purpose of engaging, agreeing to engage, or offering to engage in sexual acts or contacts with that person (4) in return for a fee.
Graves, supra, 515 A.2d at 1145 . Because there was no proof of the fourth element in this case, the evidence was insufficient to convict appellant, and her conviction should be reversed.
II
As part of its case in chief, the government presented the testimony of a police detective, Wally Papaj, whom the court accepted (over defense objection) as an expert “in the area of prostitution and solicitation.” After describing his background and experience, Detective Papaj was asked the significance of conduct like that in which appellant had engaged — “standing, waving at cars, and using words like ‘hey, babe’ and ‘hey, honey* as the cars came up....” He replied that such activity “would be prostitution-related.”
Q. [by the prosecutor]: And what do you mean by that?
A. That they are trying to get a date, trying to get the guy to pull over so they can have a talk with them and see if they want a date.
Q. And what do you mean by a “date”?
A. Have sex for money.
Significantly, Papaj did not testify — nor could he, because he had not been there— that appellant, on any of the occasions when she waved at cars and talked to the motorists who stopped at her signal, had offered to perform any sexual act in return for a fee.
In my view, Papaj’s testimony had no cognizable probative value. At most, it showed that appellant’s conduct on the evening of May 29, 1985, was consistent with the general behavior pattern of prostitutes. I am willing to assume for present purposes that it was sufficient to prove that she was in fact a prostitute. But prostitution is not a crime in the District of Columbia. What the law brands as criminal is not the status of being a prostitute, but the •act of offering to engage in some sort of sexual conduct with another person in return for a fee. See, e.g., United States v. Moses, supra, 339 A.2d at 50-51 ; cf. Ricks v. District of Columbia, 134 U.S. App.D.C. 201, 214, 414 F.2d 1097, 1110 (1968) (“a citizen cannot be punished merely for being ‘a suspicious person’” (footnote omitted)). Thus in every case brought under D.C.Code § 22-2701, the government must prove not just the defendant’s conduct, even though it may strongly suggest (as it did in this case to Detective Papaj) that she is a prostitute, but the substance of the exchange between the defendant and another person. The exchange need not be verbal (though it almost always is), but there must at least be some evidence of a communication between the defendant and the other person and some proof that the contents of that communication is within the proscription of the statute. E.g., Dinkins v. United States, supra, 374 A.2d at 296 .
Detective Papaj’s testimony proved nothing about what appellant might or might not have said to the motorists who stopped their cars and talked with her. It was apparently offered to show that her purpose in waving at cars and talking to the drivers of those that stopped, all of whom were male, was to engage in sex for money. But it is not a crime, even for a prostitute, to wave at cars or talk to passing motorists with such a purpose in mind; the crime proscribed by section 22-2701 consists of taking the further step of offering to engage in sex for a fee. To prove *176 that, the government had to present evidence of what she actually said, not what she probably intended to say, which is all that Papaj’s testimony showed. Accordingly, I would hold that Detective Papaj’s testimony was incompetent to prove any material fact, that it was therefore erroneously admitted, and that in any event it was not sufficient, either alone or in combination with any other evidence, to prove the crime with which appellant was charged.
For these reasons, I respectfully dissent.