I'd like some outside perspective on a situation that I'm boiling mad about.

If you had a guest for a week, would you ask them to do chores? Would you consider them to be a rude guest if they failed to fulfill your requests?
Would it make a difference if the guest was 18 yrs old?
If she is your 18 yr old son's girlfriend?

The girlfriend in question is my daughter. They've been dating for almost a year, and she spent the night at his house frequently during the summer. This was her first (and probably last) extended visit. Whereas we've treated her like an adult for the past few years, he has always had a curfew and chores, and has to get permission to go anywhere or do anything. His parents exercise a lot of control over him.

She spent her Thanksgiving break at his house. Before the visit she asked me, "Should I bring a hostess gift?" Since the traditional hostess gift is a bottle of wine, and she is only 18, I told her to ask her boyfriend what was expected. I certainly wouldn't expect such a thing, if we were going to have a guest for a week. He said nothing was expected. I mention this because although she doesn't have any experience being a guest for a week, she was conscious that there might be some expectations.

His parents had him do a lot of chores during his vacation. And his dad asked her to tidy up the bathroom. Not tidy up HER stuff in the bathroom, but tidy up the bathroom. She meant to, but forgot, and now his dad is mad and doesn't want her to visit ever again and furthermore they're not going to let him spend a week at our house over winter break.

She feels horrible for forgetting to clean the bathroom and she's extremely upset about not getting to spend time with her boyfriend. I'm boiling mad for her.

Obviously they don't realize how lucky they are. She could be obnoxious, noisy, into all kinds of objectionable and illegal activities. Instead she's quiet, polite (although they were offended because she didn't say 'please' and 'thank you' enough), smart, and responsible. She didn't leave her stuff all over the place. She didn't get into other people's stuff-- she felt a little uncomfortable about being asked to tidy up the bathroom because it would mean messing with other people's stuff.

This was probably just as much to vent as it was to get perspective. If you have some speculation as to what is behind what seems to me to be irrational behavior, I appreciate it, if you just have sympathy for me & her, I appreciate that too.