When I was in school we had I think 2 inspections each year, regardless of what level (freshmen, sophomore...) you were. However these were just simple fire inspections to make sure things were not blocking the sprinklers, no one disabled the smoke alarm, and all the doors were able to open fully and if the room had a kitchen then the fire extinguisher was there. Beyond that they had no right to open or look through anything. So as long as you didn't leave it out in the open it was fine. Drugs/Alcohol was tolerated the same way it is every where, if it isn't seen then its tolerated. One thing to note in this respect is depending on University rules you will also get in trouble for drugs your roommate has in the room.
My freshman year I wore very little. I was in a dorm room instead of an apartment so it makes doing anything private kind of hard. The few times I wore during the year were on weekend when my roommate went home, or I diapered up before bed then I woke up at 5 AM to get ready for work so it was pretty easy to go into the bathroom shower, and clean up my diaper and throw it away on my way to my car for work. After that I wore more often because I always had an apartment with a common living area and then the bed rooms. I still had to share a room but we spent almost all the time in the living room and I wore around my roommates and they had no idea. I tended to shower then diaper up in the bathroom and no one ever knew. Again though I had the 'convenience' of getting up at 5 AM when I wore over night to clean up with no one else awake. I also changed before showers a lot. I would be wearing and wet then I would go shower. Wrap up the diaper then wrap it in my dirty clothes and when I was done showering I would carry all my dirty clothes back to my room past my roommates and dump them in my laundry bag (I usually wrapped the diaper in a bag also). Then when I had a chance I would dig it out of the laundry bag and throw it in the dumpster outside our apartment.
I personally think wearing my freshmen year was useless. I never had the opportunity to really enjoy it and was always nervous of being discovered. You may think your roommate has class but you never know when its cancelled, ends early, or your roommate just doesn't go. You also have the disadvantage of not really knowing your roommate freshmen year. After that you will probably pick your roommates and you will trust the people you pick to not snoop.
If I was to be a freshmen again, I would probably limit myself to only wear on weekends when my roommate goes home. Like an hour after he leaves, to make sure he doesn't turn around and come back, diaper up and enjoy Friday night and Saturday. Then Saturday night clean up all the evidence and dispose it it all. I would also keep it hidden even on the weekend though. Don't leave anything out so in the event your RA comes to the door or your roommate comes back unexpectedly all you have to do is act normal until you get a chance to clean up. And most of all socializing and school work comes above all else. So if trying to sneak in diapers is interrupting either of those, then just stop trying. And don't try it for the first few weeks until you settle in to your new surroundings.