Nah, you’d spot one pretty fast when you blundered and they went to take advantage of it. Instead you’d more likely have the opposite problem where you’d veto after a blunder but still be at such a huge disadvantage that it wouldn’t matter much.
It would be pretty neat between players of similar skill level though, then I could see the hoarding taking place.
True, and I can see some fun mind-games where a player might try baiting an opponent into wasting their veto on an apparently-strong move, or by intentionally playing a weaker move that still somehow looks strong but actually masks a now-unvetoable killer move…
Maybe for players under say 1800 elo online, but for players above that this won't work -- "bluffing" isn't really a thing until you're at the very very highest levels of chess, and even then the bluffs are only during the openings and if they call your bluff you are only worse by 0.1-0.4 at the most.
It would be pretty neat between players of similar skill level though, then I could see the hoarding taking place.