They play that card as a matter of course, because once they've got you for felony false statement, that's leverage to get you to play ball on the real reason they were talking to you in the first place.

"That's a nice, felony conviction-free life you've got there. It would be a shame if something were to happen to it..."

More likely they do something similar relatively often and only spring the trap if they feel it necessary.

Yeah I didn't mean they don't trap you often, rather they don't have to use it that often--certainly not prosecute it often--and therefore the guy doesn't see it that often.

I should have made my opinion more clear, judging by the downvotes.