I have been Playing and DM-ing (I do run more RPGs then just D&D, but it is the one that I have done the most) for nearly 30 years (I was too young to get into the Original "Underground Movement") and have seen a lot of things tried.
Sometimes they worked, but most other times they were an Epic Failure.
Allowing the players to be Evil (even as a Group) is tricky.
Allowing one player to be [or become] Evil in the Group is even harder.
There has to be an understanding from the very start that there MUST be a seperation of Character and Player.
Example: What the Player says/does verses what the Character says/does.
The D/GM must know the Players in the Group very well, and everyone has to maintain a Mature (beyond Age - emotional maturity) attitude.
I would strongly advise a New D/GM against doing this.
Most of the time the Players that they have are their friends, and a single really bad Gaming Night (or Event) can ruin a friendship.
If a D/GM really wanted to do this, then I would suggest that they call a special Gaming Meeting for the sole purpose of explaining what it is that that is going on and some basic ground rules for the Games.
1) Players are to absolutely make it clear the difference between their Character and their Real Selves.
2) Any continued arguing beyond a single Debate (sadly, the D/GM has to play the role of Final Advocate for when the Debate is over) shall be considered a Disruption of the Game.
3) If enough Disruptions happen (I normally have a Strike Three Rule, but other DMs allow more) then that Campaign shall be considered to be dead, and the DM will call a new Game Meeting to discuss the start of a New Campaign, with new Characters. And the reasons for why they are returning to this style.
Normally I simply state: "I would rather that everyone in the group is involved and having Fun - then to lose the Gaming Group. For this reason, I am changing the focus of the Campaign. Here is my Idea - let me know what you think....."