Miners have no incentive to employ monitoring of the blockchain via multiple clients like Eligius did to avoid mining any blocks on the invalid chain, if they're just going to be reimbursed anyway.
Except that in this case 0.8 miners were technically mining on a good chain and it was quite hard to detect that there was a problem. My pool has been always checking if it has the same blockchain as some other nodes, obviously this cannot cover all possible cases.
No, you mined an invalid block (under the standing Bitcoin rules) and other 0.8 miners were building on top of an invalid chain.
If you were testing against multiple implementations, you could have caught the problem as Eligius did.
(Not to say you are at fault for the hardfork, but these are the reality of it)
To be clear: the 'donor' was the EFF, and their only request was that the Bitcoins be given back to the bitcoin community.
This indeed makes a difference, since those funds were unable to be used for their intended purpose (EFF legal work). Thanks for clarifying.