I think that depends on the cache. Clearly, the intent of that cache is to unlock the lock.
For others, the intent is to find the cache in a very difficult situation. For example, I recently logged as a find a cache here in Austin that lay unfound for nearly a year hidden underwater in the muck of a large, popular natural swimming pool . I spent 45min diving over and over to the bottom holding my breath and digging up rocks from the muck. When I finally found the right rock it was like the Hallelujah Chorus went off. The cache hiders included a secret codeword on the outside of the rock that you had to use to verify a find log.
The only hitch was that exposure to the elements meant the actual cache container in the rock could not be opened by hand. I tried as hard as I could to unscrew it, eventually cutting my hand, but I couldn't open that thing for the life of me.
There were so many DNFs on that little rock in the past year it was quite a proud success to find it and verify that it still existed. I don't think the cache owners mind the logged find with no log signature. But if they do, I'll happily soldier on back, pliers and fresh log in hand, and stab a stake in its heart. I know exactly where it is now.
I'm just pointing out that sometimes there are valid circumstances, legitimate gray areas, judgment calls and a larger context that may not always be seen in a terse log.
-Indigo Parrish