Originally Posted by cupsandsaucers

Never used them. Personally find them vulgar, arrogant, garish and childish. I have a business card inside my bag in an obvious place should my bag leave my side and need returned to me.

Having said that I can see from the points made above how it could be useful in certain circumstances. But I just still couldn't do it. It looks tacky and looks like I am property of the airline.