Faulty baggage scales

Has anyone ever had their bag weigh more at the checkin counter than what they weighed it the night before with their luggage scale?

Of course you have. But this is what I want to know.

Did you bravely weigh your bag, with the same luggage scale, at the checkin counter to show the rep you were in fact right??

I've never done this and I'm not sure why. I'd like to hear from you if you have and how it went down.

Also, is the real question here: do checkin bags help themselves to midnight snacks behind your back?