Yup, that's why there is a 75% threshold so your scenario won't happen. 75% is more than enough. It means on the worst case, 75% agreed to leave at most 25% behind. I doubt 25% will stick with the old chain anyway.
The other 25% which are almost 1/3 of the system are being forced to take action. If we end up being a system where the majority can push around the rest, then we are not better than fiat.
The other 25% (of the original sum) is more than 1/3 of the forked system and are being forced to take decide.
Oh look, another BTC doom theorist. Maybe aliens come and steal Gavin and your wallet.
STOP SPREADING FUD!
Two chains, twice the amount of coins. This is not FUD; this is a fact.
Whoever pushes the fork has a strong incentive to see its side of the fork be recognized as the only "universal" bitcoin
Strong incentive to test out this attack vector on Bitcoin.