Posted something rlike this ecently but this needs more attention.
Hansa implemented it by taking the market fees from the BTC payment you sent to the address, then pushing it through as a multisig payment. What this did was effectively make it no safer than escrow- as we saw, when LE took it over (or if they had decided to exit scam) they changed 2 of the 3 keys to keys they control and took all the BTC. This completely defeats the whole purpose of multisig.
Wallstreet just confirmed they do exactly the same thing. THIS IS NOT REAL MULTISIG. THIS IS NOT ANY SAFER THAN ESCROW
What about Trade Route? How are they doing multisig?
Cant comment on traderoute but I know Sourcery does it and even lets you check the redeemscript prior to sending and has a separate address for fees but given the new vulnerabilites that were discovered I would hold off on choosing Sourcery. Hopefully someone will comment on traderoute.