Sorry this is long, but hopefully it clarifies the trade loophole discussion...
In response to all the discussion about using a second trade to undo a first trade or to ontrade a player who you traded in earlier in the round...
It seems fairly clear that the software must be written so that when a trade is completed the "new" team is compared to the team as it existed in the prior round and the number of trades still available is calculated based on the number of different players.
So - trade player A to player B and then, before player A has played, trade player B back to player A. How many differences are there between the team after these two trades and the team as it existed in the prior round? Zero - hence the software concludes that no trades have been completed (even though you have performed 2 trades!).
Or - trade player A to player B and then trade player B to player C - ie effectively player A has been changed to player C and no other players have changed. How many difference are there between the team after these two trades and the team as it existed in the prior round? One (player A is now player C) - hence the software concludes that only 1 trade has been completed (even though you have performed 2 trades) - Note: It doesn't matter whether player A has played or not when you ontrade player B to player C - that will not affect the glitch at all.
In theory, the software could be corrected at any time, but that's perhaps unlikely since changing software has a nasty way of introducing other little glitches and I doubt they would want to risk that while the game is ongoing. But it's a risk that anyone trying to do this needs to accept.
For those going for the prize, the question is... does this violate the rules and could doing it disqualify you if you win?
The language in the terms and conditions is interesting. It doesn't actually say that you can only make two trades per round. It says that you can trade up to a maximum of 2 players... ie replace two players with new players. It says that you can make one or two trades at once ie at the same time. But notably it does not say how may trades overall per round you are limited to in order to replace the two players that you are allowed to replace. It says you cannot reverse trades (ie hit the reverse trade button) after a round has started but it does not say you cannot do an additional trade to undo an earlier trade. All in all, there is really nothing there that forbids the above loophole. We are still limited to trading two players per round. We are still limited to trading only 1 or 2 players at any one time. We are still not using the reverse trade button after the round has started. But I have to admit I haven't read all the fine print!