somebody said you could detect it through bitcoin itself.
just patch your bitcoin to do > 100 or more connections.
when a new block is announced have a look at the sender.
if the first announce came from btc guild its most likely their block.
its not my idea. but i am currently thinking about writing a patch for bitcoin.
So I was thinking in a way to stop this and I think its easy: Just have deepbit, BTCGuild and maybe others bitcoind client connect to the Bitcoin network throught the same proxy. The pools would still have the same chance of propagating when a new block is found because they are using the same proxy, but the pool hoopers would not know from which pool is coming because all they see is the messages coming from the same source.
Ideally pools would join in groups of 3 and 4 and create several proxies so there would be less chance of cheating and it would be more decentralized.
Thoughts?