I can understand your idea, but as a mostly pretty prudish person myself, it seems funny to me. You walk by someone and your pins both turn red, so you look at each other and start sexually harrassing each other and saying profane words. What a funny image.

Not to discount your idea--I can see value in it. It actually theoretically protect the prudes more than the profanes. I do believe that profane language or language usage in general tells people a bit about who we are, but I can't understand people that want to signal to other people that they're lower class/less educated/what-ever with the use of profanity to a stranger they've just met with a 'red' identity pin.

But in actuality, the usage of this probably won't work that way. Profanity is to shock--so the profane people would be more apt to use it around the people who's pins show them to be prudes (white?)

Why does the pin need to be electronic? If I'm 'red', wouldn't I be all the time? Sort of like wearing a lapel flag or cross? We all do things to signal who we are all of the time.