Alcohol doesn't have to play a factor. I once had a lady come over for a overnighter. I have a cat and I did not know she suffered from allergies. She knew I had a 4-legged pussy at the house when she accepted the invite anyways. Sooooooo she loads up on allergy meds. 2-3 hours into play time she flat passes out.
My main concern was that she didn't OD on allergy meds. So I checked her pulse and shook her a little. She snorted, rolled over and I knew she was OK.
I then went into the living room, watched porn and spanked it like a monkey in a mango tree. Then I snuggled up next to her and slept til morning. When she awoke the next morning and couldn't remember anything I decide to fucked with her a little. Lied and told her she took it in the ass all night long (she was NOT a back-door gal!).
And yes..she did make things right later on.