What about challenge caches? It seems to me if you attempted a challenge cache like the Delorme Challenge while on vacation in Utah, and you failed and may never come back or it may be a long time, that a DNF should be posted. I think I would. I can see the point some may make that they had not yet looked for the final, but at the same time I think it gives you a record of the attempt for yourself plus it lets the cache owner know people are attempting the cache.

I understand, if you live in Maine and are working on the Maine Delorme Challenge, that it would be silly to log a DNF every day until you logged it. But there are times when you know it will be a while before you can come back or conditions for the challenge exist which would require you to start over.