Touchy Feely

So I am 8 months pregnant and I look it. As one of the doctors asked recently “Is it safe now to ask if you are pregnant?” I realize that I am as big as a house, so people can’t help but notice me, but what gives perfect strangers the right to touch and talk to me? Some examples: I am walking down the street and a 20 something boy with dreadlocks is walking towards me as we pass he smiles and says “It’s a girl” and walks on. I am in a fitting room and the sales lady asks “Can I rub your belly for luck? (Did I suddenly become Buddha?) An older lady sitting on a park bench asks me “Are you feeling alright?” A man waiting to board the subway points rubs his belly and gives me the thumbs up. Alright, I could go on and on, you get the picture. Is there some primal instinct to care for the continuation of the species that comes out in people or are these people just weird? What is the appropriate response when a stranger in the grocery store comes up and says “Oh you’re pregnant” and touches my belly? I am not opposed to physical connections between people, I don’t mind being touched by people I know, but it is a little uncomfortable to draw this much attention. Thankfully I have always been able to smile and walk away and be thankful that this pregnancy is almost over.