Ok, I am going to be a bit of the descenting opinion here.
First of all, please read the reports on the sanitizing lotions, creams, etc....there are so many out there, trying to warn parents do not over use these ....because it is ruining our children's natural protections. If someone is sick or on a plane or hand washing before eating is not available, ok....but otherwise most people totally over use them. It's just like antiboitics, save them for when you really need them, or else you cause more damage than good.
I read one report about why kids are so sick these days once they go to school...it basically said, we isolate our children and sanitize our children so much as babies and toddlers that their bodies no longer know how the fight off germs and virus'...then they go to school and bam! are bombarded and you're not around to sanitized them and thus creates the viscious cycle of being sick.
Second, first let me say, if you truely feel uncomfortable and your child is in danger then do everything needed....but when people do this most times they are being friendly and are fostering a sense of community...these are they type of people that help strangers, help lost children and will speak up when they see something amiss...do you really want to discourage that because of a few germs? We all wonder why people don't help when someone calls for help...or step in when a child is lost or in distress....etc....why? because we continually telling people don't touch our kids, don't talk to my child, mind your own business, etc.
I hope I didn't offend anyone...just telling it the way I see it.