Not quite, there is usually more evidence than that.
There are two mistakes here: firstly, it's worth pointing out that the complainant's character is not on trial and cannot, should not, and must not be held against them. A natural consequence of that would presumably be that, say, a serial drug addict could never expect to bring a successful rape accusation -- which is to say that the most vulnerable in society would be least protected.
Secondly, the simple fact of rape is that it boils down to the state of the victim's mind, and their intents, at the moment of sex. Naturally the circumstances leading up to it shape the story, but a victim can make a whole host of decisions that invite this sort of judgement and still be raped, because at the moment that truly matters they did not want sex, be that with the person accused specifically, or just in general.
The problem, then, with bringing the complainant's choice of underwear in is that it ignores this -- of course it does, because it's a deliberate and underhand tactic. Most defences of rape inevitably, and sadly, end up trying to paint the picture that the woman actually consented, and the only way defending counsels seem to know to do this is by painting the woman as a ***, who was absolutely gagging for it, and what man could fail to be tempted by such wiles?
It's unacceptable, it's pathetic, and it's demeaning to victims.