First off, let me just say that I love the Challenge Checkers. It has made both my life, and my fellow cachers lives, much easier to determine who qualifies and who doesn't. Thank you to the people who spend their free time keeping them going.
I would like to suggest that a BIG disclaimer be put on the Challenge Checker page that you must sign the log in order to log a find on a cache even though you qualify for the challenge. I've been deleting numerous logs where random cachers, some with thousands of finds (who should know better), log my challenge caches without signing the physical log.
Most of the time it's easy to pick them out because they mention nothing of the trip they're on (especially when they're out of state cachers) or I look at their finds and they have found multiple challenges in different states on the same day. After I delete their log, I always message them telling them that they must sign the log before logging a find and I usually get a response along the lines of, "The Challenge Checker said I qualified so I just logged it"....from the safety of their living room, of course. One woman claimed that she had never heard of Project-GC and that it was doing it all on its own. What's funny is that even after you educate them, they don't delete any of their logs.