Not a problem. Just hold them to what they say. If they're trying to understand, they shouldn't be talking. Just keep reading from the card. :)

I value my time, and part of that is not just giving it out to people who are trying to waste it. At this point, it's pretty well known amongst peer and family that I'll drop 4 hours on helping someone with a sincere question and not bat an eye, but I won't put up with 15 seconds of insincerity.