Gavin Andresen - 2012-04-12 16:22:55

@s{quotedtext} @s{quotedtext} The Bitcoin ecosystem consists of more that just miners, and even if miners decided to try to form a cabal to increase inflation merchants, users, and exchanges could all veto their block-chain by simply refusing to recognize it.

I think the policy of which transactions to keep in the memory pool is fundamentally different, because miners can do whatever they like and there's not a whole lot merchants/users/exchanges or other miners can do about it. There's no way to enforce a "first broadcast version of a transaction must be mined" rule, if there was then we wouldn't need the block chain at all.

As for re-writing the blockchain if an after-the-fact, large-fee double-spend is broadcast:  I think that's covered by this case:
@s{quotedtext} @s{quotedtext} Or, in other words, you'd need to be pretty sure that you've got a majority of miners who will cooperate with you to rewrite the block chain. The longer the chain, the harder that will be (because it becomes increasingly likely that one of your co-conspirators mined one of the blocks you want to overwrite).