I get this a lot, especially when I am out with the brat in his pram. People of a certain age seem to think they can say anything and have no comeback whatsoever. I once had two old ladies tutting disapprovingly at the fact that "I was obviously a single mother on the state" and "She probably doesn't even know who the father is". They had this conversation between themselves despite the fact that I was sat right there!
The look on their faces when they were (rather sharply, but oh so politley!) corrected was priceless though.
And I always notice that older people always check my ring finger as well. I don't know why that is.
Older people seem to think that because they are older they can say whatever they want. I say that if they want respect, they should try earning it.