Fantasy Football Cheating?

The trade isn't an issue, Rivers for Shaub is pretty close and could go either way. But helping his son get an easy win shows no cl and disrespects the other participants. As commissioner you can edit anyone's lineup. I would set up his lineup on Sunday right before the 1:00pm kick off. If this is a free league, then whatever, it is what it is, but as punishment, both shouldn't be invited next year, but if this is a money league, I would certainly take issue with two team working together to create an advantage for one, and penalize them accordingly. Have other teams taken issue to this?