I had thought this was the case, but all the restricted zones I saw were open, so I thought it might be for a reason. But after going up 4 floors I decided to ponder instead the effects of herd mentality. As it turns out, you exit through the top anyway :)
Small sample size but I have a feeling they take it easy on tickets on days like today. Stanford isn't some broke municipality looking to maximize ticket revenue.
Storenvy (Kansas City, Mo not Houston)
http://joncrawford.com/post/20378314843/how-i-got-kicked-out...
I assume that's the one you mean -- I met the guy and he's actually pretty reasonable, so I think the whole thing was just an unfortunate situation.