I've only used the common bag storage area once on the SWC (Superliner - boarding in Chicago) and did not experienced any problems. As others have pointed out, the SCA does monitor the area. Of course, having a unique bag makes it easier for you and the SCA to identify the your bags. Like so many others, I use common baggage zipper locks to avoid "accidental" zipper pulls. On this particular trip, I used a luggage strap to tie my two standard sized duffel bags together to inhibit folks from wanting to move my bags off the rack and onto the floor. The SCA was totally cool with that. As it turned out, there were a lot of bags on this trip. So many, that there were times when you could not make your way from the stairs to the lower level toilet and showers without having to push a bag out of the way. The SCA apologized for the inconvenience and indicated the rack was completely full and that he was trying his best to arrange bags close to the door for those getting off the train. Obviously, he was trying to keep things in reasonable order for passengers to make their way around. This is another good reason to have your name tag on your bag.