It got locked because a Blizzard CS answered my question with this response
It isn’t that we don’t care, but we don’t generalize about a specific group or realm of players. It is also difficult to verify “quitting” verses someone disconnecting or otherwise having connection issues.
If you feel there is a viable solution on how to discourage quitting or otherwise addressing that kind of situation I’d encourage submitting feedback/suggestions so our Game Developers may be able to take it into consideration. Such feedback should be posted in the Dungeons, Raids & Scenarios forum or through the in-game submit a suggestion option in the Support Menu.
Thanks for your input though.
As for Ragnaros players, I just PM them now and tell them why they are not accepted into my groups. Community solutions for community problems