I always force carbonate my entries. Mostly because it's easiest for me to do it that way. I used to bottle condition my comp entries but I often got hit on appearance and flavor from suspended yeast. Remember you never know what kind of handling your bottles will receive...
In my opinion, those were crappy judges.
I've found it to be more of a problem in mini-BOS on the re-pour. In that case it's not that the judge is bad, but just that the beer doesn't present the same. It's hard to take another judge's word that "this beer was way better earlier" when what is in front of you is anything but impressive.
on a side note, I'll reiterate that going to two bottles for the first round of NHC last year is the best change that has been made in years. Getting a fresh second bottle was awesome.
to the OP, I prefer to force carb if possible, but the longer/warmer the wait between when the beer is filled and when it is judged is, the more my bottle conditioned beers tend to dominate. It's hard to get all that O2 out of there filling off the keg.
that said though, I believe timing your brewing so that your beers are coming into peak form for a certain competition makes a bigger difference than packaging.