An unexpected side effect of pregnancy

It has been almost 3 years since the last time I was pregnant but there was a 2 year period were I was constantly pregnant. My mom, mother-in-law and grandma did a good job and telling me what to expect without terrifying me about gestating the next generation. There was one thing that no one warned me about and to this day, 3 years later, I find completely bizarre and that is if you are pregnant perfect strangers see it as perfectly acceptable to come up to you and touch your stomach. Why on earth would that be okay? If I was not pregnant and some weirdo came up and planted their hand firmly on my mid-section I would punch them in the face. Why does pregnancy negate personal space? Is it because it sticks out? My nose sticks out further than my pregnant belly ever did but I do not have strangers lining up to give that a good petting. I know that pregnancy is a joyous time that everyone want to share in but please unless you aided in making the baby or making the baby makers please refrain from manhandling the belly. And if you find the stretch mark covered baby house too alluring not to touch at least have the courtesy to ask before you give it a good rub down.