Not here, it is a taboo subject. Jammers are illegal, and can actually endanger lives in the case of cell phones. Might as well go do a dog show and kick puppies, its about the same sort of antisocial behavior.
I will never own a cell phone by choice. The vast majority of cell phone usage I've been rudely invited to participate in (sit down next to me and start dialing), is senseless chit-chat. Although, I do believe some might become suicidal at the loss of their phone, it's hardly an emergency situation. Using a cell phone (or any other gadget, programming a GPS) while driving, endangers lives. Although, some of the really bad ones I've experienced, could be both drunk and using the cell phone while driving.
Reception in the building isn't great, there is competition for the better areas indoors, and a lot of migration in search of better signals. Don't think a low power jammer would be all that disruptive, the herd would just move to greener pastures. Seems most of the users are accustom to signal problems, without intentional jamming.