Just gonna copy-paste what i mentioned to fish (and for any other mod that goes through this sugg)

So, the way i was told when i started suggesting (and the way i understand it now) anything going into a tradeback isnt usable, similar to how if an otherwise clean user trades with a scammer; that trade is unusable. Otherwise, if the contributory sales were used, then theres no reason to not use the tradeback itself since it involves one of the guilty parties.

I realize you might see it different so ill just wait for a mod to comment until then :)