RE: multisignature transaction dangers: I'm completely convinced the (large, practical) benefits far outweigh the (small, theoretical) risks that it'll be abused by some repressive government(s).
Wait, so OP's scenario is plausible?? I thought the multisig transaction idea was suppose to have a backup wallet where you didn't need anything else to have access to your Bitcoins?
Multisig is like requiring two people to know only half of a password each, instead of both of them knowing the full password.