I film for the squad I support. I also will film other squads, so that my coach and her squad can see what others do. However, I wouldn't dream of posting ANYTHING on YouTube or anywhere else. Because it's creepy. And I happen to know that there is some guy who has filmed my squad and posted their videos without anyone's consent.
The problem is that pretty much anything can recorder a 2:30 video clip and upload it. And oftentimes competitions are so crowded and hectic, you don't see everyone who's filming.