We do a lot of military sexual assault cases with alcohol involved. It is not unusual for a complaining witness to claim they were drunk, blacked out and didn’t consent.
First, if blacked out they can’t know they didn’t consent–it’s impossible if they were blacked out, rather than them exhibiting a convenient and selective memory.
Second, we know from medical science that a person can do a whole lot of things which does include the voluntary, and apparently consensual engagement is sexual activity. Here is an example, out of many, how a person can engage in a lot of thoughtful and physical activity and not remember it.
Enter Keith Fraley, a 19-year-old second year student of software engineering at Michigan Tech college, and his tweet about his roommate, Mark, a mechanical engineering student, who arrived home wasted and managed to design an entire plane – and woke up with no memory the next day.