Wirelessly posted (Mozilla/5.0 (BlackBerry; U; BlackBerry 9300; en-GB) AppleWebKit/534.8+ (KHTML, like Gecko) Version/6.0.0.534 Mobile Safari/534.8+)
I put them on my checked in luggage. Helps me ID my luggage quicker on the carousel. (Not sure why your FF status would make your gear more attractive. Surely a frequent traveller is a cannier traveller, no?)
Luggage tags on your carry on is pointless, and a little pretentious IMHO.