In my opinion, I think it's lovely. I have three children, and three neices and nephews, from 2 years to 13 years old, and they all give me and their own mum and dad's kisses. We also were brought up with not much kissing, but I think in families it's a really affectionate and loving thing to do.
I agree with you Sandy, although I wouldn't dream of stopping any member of my family kissing my babies, I would politely ask them not to kiss mouth to mouth. Germs from the herpes zoster virus can easily be passed on this way. Talk to them I'm sure they will understand, explain that you know how much they love your son/daughter but they would not want to be responsible for passing on any germs.