Concerns

So, I went to a birthday party on Saturday for our friends' daughters, twins.  I had a lady that I don't know tell me she was taking a picture of my children because they are just so neat (or some such thing).  I was so stunned by her moxie that I couldn't say anything at the time.  I looked at my husband and declared that I really hate when someone thinks they can just do that.  I mean why?  I ALMOST told her then I'd like to take a picture of her kids, just to see what the response would be.  I didn't.  I regretted my lack of response, mentioned it to a friend at work, who came up with a phrase I intend to use next time: "I'd rather you not" or "I'd rather you didn't.  I'm just funny about their privacy."  I like that.  I'll try to use that.  Now I'm having to ask my friend to give me the lady's information to contact her.  But, she has taken it on and told me that she would talk to her since her daughter is in the same class with my friend's daughters.  UGH.  I hate to be a pain about it, but the more I thought about it, the weirder it felt to me.  What if she posts my daughters' pictures on her facebook account?  I don't know, it just kind of weirded me out, I suppose.  What do you think?  Am I the paranoid one?