Koffee,
Here in the Southern California area, I run into jerks when I bring any large package (not just the folders) on the light rail trains. I simply have a lamenated printed copy of the rules and regulations of my various regional train or bus when I board along with a nice soft nylon or canvas bag usually on the folded bike to hide it and pass it off as luggage. It is a real hassle I know. But I choose not dirty myself with going down to their level of insults. Hold your head up proudly as one of the pioneers of the new transit options-an owner of a beautiful folding bike.