I think it depends on the situation.
Last fall, I worked a local car cruise. It was very big (hundreds of cars), but I ended up working a T-shirt booth that sold next to nothing all day. Anyways, this lady walks up to the booth. She starts looking at the shirts and tells me that she is from a town about 45 minutes away and she heard about it and decided to come. I was like "oh, thats good." She says that she wants to go get her friend and then they will be back and buy some shirts. So a little while later, her and this guy come back. I was at the booth alone because the lady I was working with went to go talk to someone. They buy a couple shirts and start to walk away. Then they turn around and get their camera out. They were telling me to smile because they want a picture of me. I went behind a t-shirt that we had hanging up as a display and stood there. They moved around the tent trying to get a picture of my face. I turned my back to the back of the tent and they moved to the side. The lady that I was working with came back and asked me why they were taking a picture of the booth. I told her they were trying to take a picture of me. She told me to go to her car, which was on the other side of a fire truck that was parked in front of the booth, to get something. So I went on the other side and they followed me!!! It was really creepy. I wouldn't have been so freaked out about it had they tried once and then gotten the point and left. But the fact that they were like so persistent to get a picture of me kind of creeped me out.