As it's now a major fine for the university if this happens, they've penned in the student section to a far greater extent than it was before. They used to be right on top of the court with a virtually clear path to it, save for some photographers and cheerleaders and whatnot. Now, there's a giant metal barrier between them and the court, which is set far enough back to create a walkway between the floor and the student section. This allows space for security to get set up in between the students and the floor ahead of time. I'm sure if they really wanted to get on the court, they could still find a way, but it's way harder now, and is almost certainly not worth it for the now pretty standard home beating of Kentucky.