At the risk of sounding like a religious prude, let me point out that this sort of bill would not be needed if our culture did not merely tolerate, but encourage casual sex. If at the very least, the expectation for both men and women would be that they would at the least be "going steady" before visiting a certain village in Pennsylvania, the number of conflicting accounts (whether from differing interpretations or outright lying) of whether sex was consensual would be considerably reduced.
I tend to think that the issue isn't the prevalence of casual sex. The issue is (some) men feeling
entitled to sex with any woman they want, regardless of the woman's feelings or if there's any chemistry between them (or in some cases, if the woman even knows the man exists). The days of female sexuality being controlled by men are over, and thank Zeus for that. Yet some jealous, resentful, misogynistic men apparently haven't gotten over that development.
And there really aren't many cases of outright lying by survivors of sexual assault.