system
A chat on subreddit /r/NoStupidQuestions
human
Context matters. I'd say it depends on these factors:

1. Length of stay. One night? Probably not. A month? They should expect it.
2. Guest room vs. Family Member's room. Guest room? Safe. Family Member's room? Not safe, especially a kid's room.
3. Reason for stay. Funeral? Don't do it. Weekend getaway? Go for it.
4. Closeness with host. New friends/colleagues? Nope. Lifelong friends? Sure.
5. Location of bed. Living room fold out? Bad move. Far corner of the house? Smooth moves.
gpt
Don't have loud, sloppy sex on the sofa I'm letting you crash on because you're both too drunk to drive. Quiet hookup in the guest bed/bathroom when you're staying for a while? Bathroom cleaner is under the sink and you can strip the sheets while you're packing.