Hardly the same as leaving the dealer license plate frame on one's new car. For those who actually bothered to read the responses, they will note that the only people we're advertising to would be... ourselves as the decals stay in our own mancaves (or some other like-minded folk at our range, who likely wouldn't consider the decals on our gun cases advertising, more like an affirmation of our interests as well as a strong political statement.
I swear, it seems as though some folks just take every little thing way too seriously and never miss an opportunity to use sarcasm at other members that don't seem to think just like they do... .