You should have screamed "Terrorists!" and then thrown yourself into a flying body slam, WWF style. Smack down, baby. That would teach them to try and buy "bullits".
I'm just teasing, of course.
At varying times, I range between redneck and yuppie in appearance. And I've bought ammo in each of my guises.
That said, I have seen guys I thought to be "bangers" at a local range. What made them suspect, in my book, wasn't how they dressed or talked. It was the fact that they put up a silhouette target at close range and then insisted on emptying their mags rapid fire, much to the chagrin of the RO. He finally asked them to leave.
But then again, who knows? Maybe they were undercover CIA and needed to get in a little practice.