MIL did that to me - we told his parents at 11wks, and after a hug goodbye, she rubbed around my navel (a good 5 inches above where baby was, and in an area where I have a good 2 inches of flubber)...
The only ones besides her have been DH and OB (no problems there)!!
I know several ladies who are just waiting until I'm big enough, but they know me well enough to ask first...I hope. Pretty sure.
My baby sister is having her third in a few weeks, and at Thanksgiving, I asked and got permission to touch - I always ask, and only family and friends!! Never strangers! Seriously!