Stranger Danger

I don't want to be one that poos on the Christmas spirit, but being a Mommy this is something that I have to think about.
Last year we did not take Jonathan to see Santa because he was just over a month old, and had been sick off and on. I did not want to chance that he would pick something up in the mall. So, this year after a lot of thought I decided to take him. Jonny is amused by watching people. When we go shopping he is so well behaved (usually) and he just looks around and watches people as we go past them, always getting attention with his heart melting smile. He just loves being told how cute he is.
Anyway back on subject, while this is a great quality to be such a people person, it is also cause for concern. He is a very trusting baby, sort of someone wearing a Halloween mask I think that he would go to almost anyone.
The reason for concern: SANTA. How many Santa's are there out there? How many are good Santa's, and how many are bad?

Good Santa
Bad Santa

We try to teach our children not to go near strangers, but we encourage them to talk to Santa. When children are young, they only know to see the good in all people. Why would they not want to talk to Santa, or go to the North Pole with him? To often kids are tricked into going with strangers, it seems far to easy for a Santa to do the same.

I wish there was a way to educate our children, but not ruin the Magic of Santa for them.
Besides that how long before they start to realize that the Santa in each mall, or Salvation Army collection spot looks different? Maybe I think about all of this because I don't have a young child's imagination but what do you say? Let me know if you have any ideas.