How does one detect a fork?
Run several versions of Bitcoin and if they start to mutually deviate over three blocks then that is either a fork or is, a least, sufficient reason for merchants to go into safe mode. Sounds to me like a business opportunity.
Actually, if this is implemented, it would make it much safer for alternative full Bitcoin clients to operate because we could detect the inevitable chain splits quickly and safely.
You're reading my mind bro.
Any service handling serious amounts of BTC should be running a .7 (stable) and a .8 (beta) while checking the outputs for diff.
Also, why didn't .7's large block problem show up on testnet?