I'm noticing a recent marked increase in F cabin seatmates and near-bys who just can't wait until we are on the ground to turn on Blackberries and I-phones and Androids to collect emails. I'm really not a believer that our devices are real hazards to navigation systems in planes, but rules are rules -- and of all places where we should be concerned about interference, final approach is #1. Sure would love a strategy to seek compliance without creating a confrontation, or feeling that I'm overstepping my role as a passenger. Any suggestions?