Today I stumbled across another useful feature of my beloved TaskWarrior: One can assign an urgency-coefficient to tags (and this coefficient can also be negative):

urgency.user.tag.maybe.coefficient=-100.0

I use the maybe-Tag to store ideas that I may or may not approach one day. Once a month and whenever I feel like doing something "useless", I can review the list and have every idea at one place (and I am always able to store such an idea). But of course I want to prevent +maybe tasks from showing up in reports like "next". This feature with a negative urgency-coefficient achieves exactly this. You can find more Options at the TaskWarrior documentation.