yeah, "formatting" in the discussions, well, kind of isnt. it was a design choice, for better or worse. ''keep it simple''. it works if things are, well, simple. (not good for organized complex posts like yours... sorry.)
anyway .. i like your tag suggestions. i have been using "reservation joke" for what you call "reserved". either way i like all of them. i considered "quilty" myself -- but i know its a judgement call (theoretically), so i chickened out!
here is a tiny secret. someday(!) tags will support "equivalence". what i mean by this is that we will be able do some admin magic and make, for example, "reserved" and "reservation joke" be the same, as far as searching and such is concerned. so dont worry too much if there are identical meanings in multiple tags. oh sure, it might not be available for a year or so, but.... haha
(also, we hope to have language support as well; i dont know how you would say "quilty" in french, but you could once its there, and it will be the same thing.)
finally, regarding finding untagged levels. thats a great idea. i will see if i can whip something up. til then, RANDOM is a kinda fun way to find them...