trade champions in draft mode fails?

hey, not sure of the details, but I have had a bit of an issue myself with this in the past.

I was in a ranked game, two players on my team agreed to trade early on, then, at the end, they both agreed to the trade, but it simply did not go through, and both players were stuck with champs they weren't very familiar with. Naturally lost the battle; it's disappointing to go into a game in such a way.