There is an easy fix for people fishing por one or the other: change it so they can't fish.

Example: you queue for MSQ roulette and get Castrum. Well, Castrum is what you will get everytime you quit and queue again for MSQ roulette for the rest of the day unless you complete it. Problem solved.

If you are going to tell me that you will not queue again if you can't "fish", that's fine then. The reason I don't queue for it now is that half of the party will quit if we get Castrum, so things will even out anyway.