I think they put safeguards in place to prevent that. Even if so, I think we can all agree to not accept that offer in that case. Unlike the current Coach Contract system, if you're a decent candidate you shouldn't be hurting for offers ... I would expect that once we start generating offers, we'll see at least a few each season.
Since they've announced that User vs User games will be played with the user having control over both sides of the ball, I don't think there'd be any way for two users to be in control of one team.