"Do Jehovah's Witnesses count?"

IMHO, yes.

However, whilst a Jobey will bugger off if you tell him/her you're a practising RC, a 'normal' salesman (if, in fact, any salesman could ever truly be deemed to be 'normal' in any accepted sense of the word) won't turn a hair, and will just keep on with their crappy patter and the foot-in-the-door until you get savage and tell them directly to Foxtrot Oscar. :-)