Um, it is a big deal if you don't like it.
And if some of you are okay with other family members/friends/strangers touching your pregnant belly, then that's a-okay.
But it's not cool to the OP, and she has a right to not want people all up in her space rubbing her stomach.
Sorry, but if you're threatening a family member with a broken limb over a belly rub you are a Class A douche.
I'm more inclined to believ women who think their way of going through life is the only "right" way to do things is a "grade A-douche."
Every day moms make decisions over BF vs FF, natural birth vs. c-section, SAHM vs. WM, homeschooling vs public or private school. A choice different than what you choose isn't wrong or mean someone is douchey, just different than what you would do.
And that extends to who and what touches our bodies, family or not.
Now get down from your high and mighty cloud.