Looking over the (Google Translate of the) RebusRally #100 announement, something caught my eye:

If the team has immunity (ie, at least half of the team has put rally with the team name)

I wonder if they have a system like BANG, where you might find yourself obliged to run a future event if you win this event. And if, to avoid having the same teams running game after game, they introduced an immunity rule. Looks like it.