I don't know which was the worse decision, but the bad break that JVV got was far far worse than the one Romero got. If Romero's ball stays in the burn instead of going OB, he drops, hits 4 onto the green, and probably still makes 6. If JVV's ball goes anywhere else besides exactly where it did, he couldn't help but win the tournament!
Besides, the shot that Romero hit was WAY worse than the one JVV hit, so he didn't exactly deserve anything great to happen there.
Either way, Romero's caddie and Jean Van de Velde's caddie should be the charter members of the Bad Caddie Hall of Fame--at some point you have to be able to know the situation and talk your player out of taking an unnecessary risk. But I know that's probably too harsh--the truth may be that caddies, too, have to be able to control their emotions and decision-making just as their players do, and until they've "been there", they too are prone to mental errors that can lose major championships.