All I can say is...if you snap a picture with the phone, ask permission somehow first.
I know that the girl I'm talking to was out eating with her twin and two friends, and they noticed that as her twin walked by a table with a group of 30-something businessmen, they were trying to take pictures under her skirt and such with their cellphones. Same thing happened to the girl herself when she went up to get food. Only after the entire group started making obvious/loud remarks about how rude it was did one of them come up and ask permission...at which point they all gave him dirty looks and left.
Good lord, older men can be creepy, disrespectful, and disgusting sometimes. Scratch that. Men as a whole can be creepy, disrespectful, and disgusting sometimes.