do whatever you want, tbh if you live in halls you're gonna hear someone have sex, that's just how it is... the walls are always paper thin and the beds are often crap and creak a lot - it's polite to put on some music and not to subject your flatmates to listening to you scream or forcing them to hear your fetishes or something but other than that it's just a fact of life, you stick your ear plugs in and carry on
I'm not quite sure why prior warning a man was coming round would help... is she going to sleep somewhere else? I doubt she's wandering around in revealing clothes when men aren't there or something... but either way asking for notification of when you have sex is unreasonable and weird