Personally I configure ssh-agent to have my key decrypted in memory, but to bring up a simple yes/no confirmation dialogue whenever an ssh connection requests t

Personally I configure ssh-agent to have my key decrypted in memory, but to bring up a simple yes/no confirmation dialogue whenever an ssh connection requests the key. While it doesn't prevent the problem, it certainly increases the sophistication required - I'm not likely to click on such a box when I haven't done something that would need it.