I do think way too many security guards and cops overreact when it comes to people taking photographs. I'm pretty laid back about it personally .. the only time I'd stop them is if they were trespassing, taking photos of restricted property or interfering with my job.
I had a couple once ask if they could take pictures of me and my cruiser.. I just shrugged and said sure. It doesn't bother me.
Some cops freak out about it though. Maybe they're just camera shy. lol
I had a female cop in Portland get all bent out of shape because I took a photo of her texting on her cell phone while she was uniform. I don't know if there's some rule against that, but her reaction suggested there might be.
I told her not to worry, that I wouldn't show it to anyone, since I felt the pink iPhone cover clashed harshly with the deep blue color of her uniform.
She then let up, smiled, and told me and my buddy to have a nice evening...