[Epistemic status: still not entirely sure if I understand this category of anti-YMY arguments; everything beyond the second paragraph is speculation I’m throwing out in the hopes of correction.]
A point that it took me a surprisingly long time to understand:
There are two things that people are talking about when they’re discussing false rape accusations. The first is a false claim about the facts of the matter: for instance, someone saying that they said “no” when they said “yes”, or that they were unconscious when they weren’t, or that an act of penetration occurred when it didn’t. The second is a true claim about the facts of the matter that the person speaking believes should not be ethically considered a rape.
Initially, I was puzzled when people said that Yes Means Yes laws would increase the risk of false rape accusations by loosening the definition of rape. It is already possible for anyone to make a false rape accusation after sex: I can have sex with someone and say “I said no! He heard me!” and barring Third Eyes you have basically no ability to prove me wrong. Drunk girls who regret having sex are already fully capable of falsely accusing their partners of rape. Yes Means Yes laws do not change this.
(The preponderance of evidence standard for rape cases on the college level does make it easier for someone to get someone else expelled with a false rape accusation, but that is not a new change– it has been the law of the land for years.)
However, I believe that people are not discussing false factual claims. The situation they’re afraid of is that women will have sex, possibly while drunk, and fail to give affirmative consent; when the sex was a good experience, the women will not prosecute, and when the sex was a bad experience, they will.
The question of how to balance punishing rapists against the risk of false factual allegations legitimately a Very Hard Problem. People claiming that acts of abuse occurred which did not occur are, in fact, are a common tool of abuse; it is unwise to give abusers the ability to isolate someone from their friend group simply by saying a word. At the same time, most rapes are not provable beyond a reasonable doubt, and this does not look like it is going to change. The only solution is nuance: the victim’s best friend can believe him unconditionally, social circles can believe the victim if the accusation seems possible, the courts require evidence beyond a reasonable doubt.
However, I’m not sure that the second one is much of a problem. I can think of three circumstances where it comes up.
First, the victim may legitimately feel as though she were raped. In that case, I’m not sure that it is fair to call it a false rape accusation, since according to both the victim’s lived experience and the rules of the school she was raped. However, if the accused genuinely believes that the sex was consensual, this may be one of the few cases of the fabled Rape By Mistake.
Second, the victim may be vengefully attempting to destroy the accused. I’m pretty sure nothing changes, because as I said above a person can already falsely accuse people of rape and get away with it under the current system. There might be a small population of vengeful destroyers who also stick scrupulously to the facts, but I feel like the overlap between “wants to destroy people’s lives for no reason” and “Kantian objection to lying” is fairly small.
Third, the victim may have viewed his experience as a bad experience without Yes Means Yes laws, but under the vengeful influence of campus feminists come to see it as a rape, when he otherwise would not. Interestingly, this is exactly what Yes Means Yes advocates want– they would like people whose partners did not seek affirmative consent to consider themselves rape survivors. I suspect the difference here is related to different factual beliefs: Yes Means Yes advocates believe that the victim would be traumatized either way, and telling him he’s a rape survivor will help; those concerned about Yes Means Yes worry that he would become traumatized when he otherwise wouldn’t have, because he has acquired the label of Rape Survivor.