Please don't touch my child!

I really need to rant and vent about this one.

I walk my son in a stroller a lot, as I like going to the distant park, or a water feature, or visit friends. Its a great exercise and.. you know... no car and all. So yes, I meet a lot of nice people walking, jogging, biking and moving by other means. I'm not talking about cars here, I'm talking about those nice people who pass by.

Many people take a minute to stop and wave to the cute toddler in the stroller, say "hi" and wish you a nice day. Some people, mostly older ones, but also an occasional young weirdo, would go ahead and start touching the toddler in the stroller, pinching his cheeks, hands, and stroking his head. I get annoyed beyond calm words by this. Unfortunately, I have not found a way to tell them to not do it, I just move the stroller, say "bye" and go. A few days ago one weird guy stopped and kissed Santino, saying "oh, how cute".

Can I just say something? DON'T TOUCH MY CHILD! (I really wanted to insert an "f" word here, but decided to keep it decent, just for the sake of it).

Your hands might be dirty, you might have just sneezed or coughed in your hand, you might have just been smoking a cigarette, or shook a hand of a contagious person. All kinds of things might be propagating on your hands and elsewhere on your person, so why the ... do you touch somebody's child?

I was brought up so I don't touch anybody, until we are practically family. Before I had my son, I heard once that stroking a pregnant belly can bring good luck, but even then I didn't allow myself touch anybody's belly, but my own. I understand, that it is very private, and touching it without invitation is violation of the woman's personal space. Nobody ever cared about that when I was pregnant. Everybody would just help themselves to touching me, my belly, as if I was a golden laughing Buddha. Very annoying. The most annoying part, is that I try not to hurt anybody's feelings, so I never actually said out loud "please don't touch me".

But I am growing confidence, so next time - back off, you nice little old lady! Please don't touch my child!

Suggestions on how to keep people's hands off my son are welcome.