I think the identification of challenge caches by title is not sufficient - I know a few in my area missed by this approach. Shouldn't there be a curated list of challenge caches, seeded with the unknown having the word "challenge" in the title, but then (community) edited? Please remember that habits for challenge caches are different especially in countries which are not so anglophilic
This would also make it easier to identify caches with missing checker and give a more precise number for the coverage
Opinions are welcome!