I don't really see the sense in doing that.
I mean, I waste 20 minutes in a queue. A 2/3 pops, I join. I kill the boss, then I sit another 20+ minutes to get a 0/3. I go in, kill the two bosses and leave, like half the raid.
I saved a doomed raid just to throw in the garbage another 20 minutes of my life and doomed a second group.