I have never heard of, thou I'm not that deep in the circle of gossipers, people getting written up for not staying in the break room on break. If it does happen, and they ask team members why they are doing it, they don't understand the social culture of the team (Overnight in this case).
I'm sure there are stores like this where people break off into cliques and don't socialize or interact with other team members. Mine is so bad that I've seen people actually use the dressing rooms to hang out or they even sit near one of the entrances. Some of that largely has to do with the fact that alot of team members start out friends with each other (supposedly) and then after they get to know them they develop a deep-disgust for that person (or group of individuals).