Why do security guards always come running when they see someone taking pictures with a DSLR but they'll let hundreds of people snap pictures with smartphones?
As a former film student this drove me crazy. Every now and then for a student film we would do run-and-gun/guerilla filmmaking, where we would find a good looking location, drive the actors there and quickly take a few shots with a small camera, taking care to not get any logos and stuff in shot. A security guard would inevitably spot us and come running, demanding that we not film, yet hundreds of people take hundreds of pictures and videos with their phones all around us.