I agree with the public property guess. And it's a long-term behavior, because my last baby was 30 years ago. I hear friends who are currently pregnant bemoaning the same lack of respect for their boundaries. People
do touch without asking, ask very personal questions*, make can't-you take-a-joke remarks about their weight or increased bust size

. It's not just people who know them, sometimes it is complete strangers.
And don't get me started on waiters who inform you you don't
really want the food you just ordered because they read somewhere it might be bad for pregnant women. I was actually present for that one. I got up and went and got the manager.
* Personal questions I was asked by strangers when pregnant- was it planned? was I going to breastfeed? did I expect to have a vaginal delivery or was I likely to need a c-section? had I gotten to the stage where I didn't want to give my husband sex anymore? Look, I realize that pregnancy is very interesting to some people and all, but- sheesh.
*boggles*I can barely accept that people can be so invasive about the whole thing. I mean, buh... !!!!