Generally the advice from maintenance has been that "normal living" is allowed, and thus we would assume some holes can be made as long as you use your common sense. You should also remember to cover up any holes when you move out. The materials in the walls are pretty diverse, and you can get advice and tips to properly making holes from maintenance. They might even let you borrow a drill if you ask nicely. It's in everyones best interest that the holes are made up to a standard.
Holes in the bathroom walls however are NOT recommended! They are always problematic due to plumbing, and the holes also need to be properly sealed to keep any moisture from getting into the structures. If you for some reason absolutely have to make a hole in the bathroom, please contact maintenance before you try anything yourself!
The resident council encourages using common sense when it comes to making holes. The provided tips are in no way the absolute truth, and everyone is responsible for their own actions!