@Finn dAbuzz,
This isn't just about "frat boy humor"--it's also about frat boy behavior and how women are regarded and treated by many frat boys, and college athletes as well--and it involves an acceptance of sexual assault, and a normalization of sexual assault, and an entitlement to commit sexual assault, particularly on someone who is intoxicated. And, while this is certainly not true of all frat boys, or all college athletes, it's been true enough that a good many colleges now have special sexual assault intervention programs for these groups.
This bill will, at the very least, make it clear on California's campuses, that, in order to consent, the person must be awake, fully conscious, under no threat or duress to comply, and must demonstrate, in some way, that the sexual contact is clearly wanted, that it is mutually wanted. That alone will, or should, make people stop to think about what the other person wants, rather than just what they want.
The bill is not intended to solve all of the problems regarding sexual assault on California's campuses, but having a clear definition of consent as "Yes means yes" requires some degree of respect and alertness for what the other party really wants to engage in--enough to actually inquire about what they want, rather than simply waiting for them to resist or say, "No". That alone is a good start to dealing with the issue of sexual assaults on campuses, and trying to reduce it.