I don't know about the rest of you, but I have people constantly trying to rub my belly.  Complete strangers walk right up to and start touching me and it drives me crazy.  I was watching the local news and they showed this woman who created a line of maternity shirts who don't want their bellies rubbed.  They are hilarious!!  My favorite is "Please Celebrate the Miracle of Life from Afar".  I'm ordering a couple of these, especially for those days I'm not feeling well and absolutely don't want people touching me. 
The website is www.sarcasticstore.com

Here's the link to the local news story for those of you that are interested.  http://www.tampabays10.com/news/local/story.aspx?storyid=88224&catid=58

I am 100% in agreement with you about strangers and even people you know touching your belly like it is some sort of new greeting.  It really makes me feel uncomfortable. The last lady at my work that rubbed my belly, I rubbed hers back and boy did she get the point quick!    Someone posted another site here once that was my favorite was "unless you are the person who put this in here or you are the person who is going to take this baby out, hands off!"

Oh the fun parts of pregnancy!  It is all worth it in the end but it is good to know we all share the same scenerios.

I haven't really had anyone trying ot rub my bellly yet but that is becasue i am barely showing.