A-holes are a-holes, no matter what tools you give them. If someone adds everyone just to make fun of his/her friends, then the question is not so much about motivation, but rather why he/she still has friends at all.
I imagine most people after the age of 18 stop doing that, so I guess this might solve a problem provided there are some age limitations. Then again, you have to wonder if people older than 18 have 'crushes' they can't resolve like adults.
You Americans make it too complicated :)