Party thingy

Okay so i went to this party thingy with my family and i was waiting for my niece and my sister to get done getting their face painted and some dude was sitting next to me (because i was sitting pretty far away) and he kinda had his phone out but not covering his camera in his pocket. I SAW HIS PHONE FLASH AND TAKE A PICTURE OF ME. (also his sound was ALLLL the way up so i heard it too)Bro i was so scared i was just trying to get away from him. I don't even know how long he was following me but it was probably for a while. Out of every seat he chose directly next to me. Mind you, 90% of the seats were empty because most people were sitting at tables or standing. (We were sitting on stools) And i'm just kinda freaked out that a picture of me is on some strangers phone. He would also look at me a few times to make sure i wasn't looking at him. 

when will people realize that taking photos and videos of strangers is really weird. I don't know who that dude is but i hope he deletes that picture and gets some help because that's insanely weird.