Hotels in Magaluf, Mallorca?

Basically, I'm planning on going away with my friends to Magaluf next month. The problem is I cant get a hotel room in the right area or for an acceptable price. However, my friend has paid full price for a twin room for himself, he has offered to let me stay in this room free of charge for the week. If I was caught doing this would I be in trouble with the police and kicked out, or would it be acceptable? Thanks.