No your not paranoid, but if one really goes down that Rabbit Hole you would never go anywhere. People shoulder surf at stores and gas pumps, your rewards cards track everything you buy as does your credit cards, warranty cards you filled out and sent in , your mortgage information and such on file at the county or state level, if you live in a small town any delivery to the house is noted, any organization you belong to etc etc etc etc . So in the scheme of things personally handing a card to someone at a rally I would imagine is a fair bit safer then say going on a big shopping trip to Wally World. Yes we had it happen here last year on Black Friday folks were watching who came out with big ticket items and following them home later breaking in to steal said items. Just my thoughts, I guard my privacy diligently but sometimes you just have to let it go.
Cypher