Quote from: Gavin Andresen on May 07, 2012, 10:09:03 PM

The attack we're talking about is "51% attacker refuses to include anybody else's transactions in their blocks." And newly generated coins are useless to miners if they can't get transactions that spend them into the block chain....

I agree, that THIS attack is probably useless. I understood the OP differently (he only had the 51% part in his question).

Quote from: Gavin Andresen on May 07, 2012, 10:09:03 PM

Miners won't switch to a 51% chain if it means they can't cash out the coins they're creating!

Agree again. "They can't cash out the coins they're creating!". Where do you take this assumption from? The 51% miners would, in my version of the attack, switch to a chain, which is more profitable for every participant (eg. they add 1 BTC to every address) - and they would continue to include transactions nto the chain. So there is a monetary incentive to switch to the spawned chain. It may take a while, until all wallet users switch to the new chain, of course. So it is a matter of speed of adoption.