They want you their early because the stewards really struggle when everyone turns up at once. It's almost more fun watching them try to cope as everyone surges in mid rally than it is watching the tennis.

The other issue is that the seats aren't allocated, only the stand. But once you're in the complex the tickets aren't checked that closely. So for example, there are Upper A and Upper C sections, but most people just walk to the nearest staircase (which is A I think) and are allowed in regardless of which ticket they have. This means one side is overcrowded, with people sat on the steps, while the other side is half empty. It's the half empty side that the TV cameras point at.