I work in a specialty store. I am one of those clerks you describe. I am sure I have given that "blank stare" when a guest asks for an item we either don't carry, never heard of, or isn't accurately described. We are expected to be experts in sewing, quilting, knitting, crochet, felting, upholstering, embroidering, beading, and even weaving. Give us a break please. We can't possibly know everything.