The problem with that is if they answer, "no, I need this or that," then you have to go help them find it or call someone to go help them find it, meanwhile there's a line of people waiting to check out, and you're halfway through scanning their order, so you have to cancel it out or wait for them to come back to finish processing them. It's a bad situation all around. Really it's best if you just ignore them and let them find their own way.