Well, if you have a boyfriend / girlfriend you could be having illicit sexytimes.
Yeah. While your parents are home.
If you're suffering from some form of mental illness you could be self-harming (god, I hate that word), breaking shit, sulking, crying, etc.
Which is a valid concern.
If you're a generic teenage fuckup you could be drinking / smoking / doing drugs.
Most of those would be foiled by any kind of working smoke detector. Or, you know, wondering why your son just shouted about raptors eating the gnomes in his closet, which I'm sure raptors are wont to do.
You've gotta assume the parents taking the door away are either uptight moral / religious conservatives who are terrified of their child disgracing them in the eyes of the community or they're white-trash who don't know how to deal with problems other than using blunt force.
Or, you know, worried about their kids. Maybe they don't know how else to react, to keep their kids from doing dangerous/illegal things. I don't have
to assume anything like what you described.