I brewed a BB kit and added a small amount of caramel extract to the keg after trying it in a glass after it was carbed. I took the keg to a party/bonfire and it was empty within a matter of 2 hours. Everyone who tasted it (including those who say "I don't drink beer") had several glasses of it.
I learned to label my fermenters. I wasn't paying attention when I racked to keg and racked my pale wheat. I meant to rack a cream ale that was right next to it for a party tomorrow. Talk about surprised when I drew a pint to test it.
I would rather drink flat beer than risk over carbing another keg myself. I learned the hard way with the very first keg of home brew that it is better to just be patient.