If you don't get caught while on probation you should be fine, unless of coarse you get busted for dealing. If you are smart, you won't get busted in the dorms. If your hallway reeks of weed, then the RA is going to have to do something, because he/she is gonna get heat from their boss. In general no one really cares about anything, saving face seems to be more important than actually having a drug free campus. Don't put authority figures in bad positions (ie, the smelly hallway) and you will be alright.