No pictures at NRG Stadium?

Hey y’all quick question! I’m in Houston traveling from Missouri, and stopped by NRG to mark it off the stadium bucket list. When I went to take a picture in front of the stadium from outside of the perimeter fence my wife and I got yelled at for taking the picture by security of some kind. They told us no pictures were allowed. Is there some kind of reason why they don’t want you taking pictures outside the stadium? Not mad just curious mostly! Thanks ahead of time!

-A traveling Eagles fan