Team A and Team B are fighting for the last playoff spot the final week or so of the regular season, but are not playing each other. In order to better his chances, Team A proposes a trade to B's opponent (Team C) that sends a strong RB(say, Edgerrin James) that he didn't need this week in exchange for a Tier 2/3 WR(ex: Nate Burleson) he doesn't really need or want. The trade deadline was week 12 of a 13 week regular season.
This happened in a league last year, but Team A still ended up losing out (Team C was also a non-contender). It takes 5 teams to veto a trade. If the league fails to vote it down, should the League Manager cancel the trade as collusion, or let it stand as acceptable (if imaginative) strategy? Even if Team A makes the playoffs, he's without a strong player.