Ahhhhhh well I see. Most colleges I guess don’t have specific restrictions against it, especially since it is your own space and you don’t have a roommate. Given what is written above, and assuming that you are the one with the overnight guest, I would assume that it is courteous to let your people sharing the bathroom know ahead of time - or just establishing an overnight policy with them. Bathrooms are fairly private and you could always just lock the door or use a public bathroom on a different floor, so I can’t imagine it being too big of an issue.