Can something like a forging mode be added? In that mode, the account participates the network but passphrase need to be entered to send money out.
In this way, it will be more safe for forging. There will be less security problems when the account owner leaves the client running while not sitting in front of the computer. It will also encourage people to participate the network by relieving their worry about the security. Of course, one can protect the account by locking the screen when going out. But usually people do not take their computer passwords as seriously as the passphrases of their money accounts. A very complicated computer password is a headache for daily stuff.