One of the two people I mentioned earlier who were known rape victims was raped at a party of all known friends, by a friend, in a house owned by a friend. We'd all known each other for years, grown up together, etc.
She had drank a lot, so we made her slow down, eat, drink water, and put her to bed. Another friend stayed in the room with her, sleeping on the floor in case she needed anything.
After the friend was asleep, one of the guys at the party (who I had known for at least 5 or 6 years at that point), came in and raped her. It was never reported, and he doesn't consider it rape because she "consented." The friend on the floor didn't wake up.
He was completely sober, and had only stopped by the party after work. He was intending to drive home, so he had MAYBE two beers the entire time he was there.
This is someone I would have imagined incapable of doing this sort of thing.
The horrible reality is that a disgusting number of rapes (as if there's such a thing as a non-disgusting number of rapes) are committed by people who know the victim. Avoiding environments with strangers might reduce your chances of being raped (I don't know - maybe most non-forcible rapes are committed by known assailants), but it's not going to eliminate them.
And I really don't feel like engaging in victim blaming in either case. It's not a woman's fault she was raped just because she went to a party. It's the rapist's fault. She has the right to go wherever the **** she wants, do whatever the **** she wants, and not be blamed for being in an environment where it would be easier for some monster to harm her.