Currently, setting up a multisig is quite a feat. Users have to exchange public keys, work out how to get the public keys from their addresses. If one of the parties are not savvy enough, an malicious party could easily be setup that was 2 of 3 instead of 2 of 2 where the malicious party generates the multisig address+script and thus be able to run off with funds anyway.

It's also terribly complex to generate and keep track of. There's been a nice attempt at creating an browser interface at coinb.in/multisig but it still lacks the kind of ease with created by the payment protocol. If there was a BIP then it would go a long way to aiding future usability of multisig wallet implementations.

What are your thoughts?

Drak