Off-limits establishment for university students legal?

There was a shooting at a bar that injured 2 university students who attend the same school as me. An e-mail was sent to all university students saying that the bar at which the incident occurred is now off limits to all students until further notice. It also claims that any student who violates the policy can be subject to judicial action that could result in suspension or expulsion as well as possible criminal prosecution. My question is if the policy is legal and under what conditions? I am of legal drinking age and I have no interest to ever visit the bar but I'm curious if this is constitutional. Thanks...