Buyers arent affected, move on. Vendors, each ms tx include an addresses from your electrum wallet, all a buyer has to do is begin a 2-of-3 tx with you to get an addy from your wallet, once they have this they can watch that address connect to other ones in your wallet as you move your funds out into a mixer.
The only real threat from 2-of-3 is that LEA can watch how much you make. This may deanonymize your laundering method by linking volumes. If that is a concern do not use it.
This is not a concern with centralized or 2-of-2 (hansa/outlaw - between market and vendor) as buyers dont see your electrum address.
so by this logic, vendors should also avoid direct deals? On top of that you think LE isn't on the staff at every major marketplace?