It’s not that easy. I’m a fraternity adviser. One of the latest tricks is to yank the condom off during sex and climax inside the female, exposing her to whatever disease you might have. The female considers that “assault”. Then there is roofies, which look exactly like consensual sex the next morning.
I understand that requiring real due process would make assaults like you describe hard to convict. That may be the price that has to be paid.
Perhaps it would be a good thing, if girls stopped having sex with guys they couldn’t absolutely trust, and if girls stopped getting drunk with guys they didn’t know.