Saying "extra scrutiny is justified solely on the basis of who proposes a trade" opens an enormous can of worms.
I've posted this before, but the immediate question such a philosophy of "extra scrutiny" raises is: where do you draw the line? If trades between brothers can be questioned, what about between cousins? What about third cousins, twice removed? What about people who are friends outside of WIS? What about people who have never met outside of WIS, but have developed friendships solely because of this site? What about an owner who gave you a lot of help when you first joined the league? What about an owner who donated you a free team - as several of us have done for other owners for various reasons over the years?
Most of us don't know each other at all except for a handful of interactions on this site. No one knows who is related to whom. No one knows who is friends with whom outside of WIS. No one knows which owners have helped which other owners out with advice inside or outside of WIS. It is, in fact, not possible to know these things. And it would be ludicrous to suggest that any of us in any league should need to explain our relationships - if any exist - with any other owners in the league.
The merits of trade can only be justified - or opposed - based on the value being exchanged.