We've got a fantasy football league at work and it's should be banned.
It brings an unnatural reaction from the contestant.
People suppported one team and you followed them. You now find that people are cheering for an rival team just because they got players from that team in their fantasy team!
The icing on the cake is when someone has a go at a player of your team, just because he got booked or substituted, so loses points.
Forget that that player may be a consistent performer, football wise.
Ban this evil thing at once, before it transforms football rivalry for good!!