Hypothetical scenario: I'm the comish of a Yahoo league where the trade veto is set to have the comish approve/reject all trades. I'm the proud owner of both David Price and Jeff Niemann. Considering them both to be sell-high candidates, I propose 5 trades to various teams in my league, each one Price+Niemann for a 2nd-4th round underperforming/injury question hitter (Upton, Sandoval, Cruz, someone in that range). Team A accepts the deal (let's say, Price+Niemann for Justin Upton) and the trade comes back to me to either allow or disallow.
First of all, if teams B, C, or D accept their version of the trade, will Yahoo even allow that to happen, or will you get a "player is in a pending transaction" message? Second, assuming another team COULD accept the offer, would I be ethically obliged to NOT pick and choose my favorite trade and just accept the first offer?