A bowling ball stored on a shelf is a potential hazard. If you are worried about it don't put your ball on the shelf and return your phone. Done and done. A mass returning would be more powerful than anything the FCC can do anyway.
I did return mine. The hazard is still there even though I returned mine. Imagine the horror if someone you loved had a heart attack and while laying on the floor they look up and see someone who was too stupid to return their Iphone 4 cursing the thing because it has no service and they can't dial 911.