Recently, I posted in the Groundspeak forums about doing maintenance on other people's caches. This was quickly dismissed and considered a stupid idea.

I did some more caching today to find that some of the caches had their logbooks replaced by other members of the geocaching community. I even found someone who couldn't find the cache, so just left another container (Which I think would be the wrong thing to do).
So, now a little confused about what is the right thing to do, I'd like to know what other UK cachers think about what you'd do in this kind of situation.

Do you replace wet logbooks?
Should damaged containers be replaced?
Should missing containers be replaced?
Are US geocachers not as kind and considerate as UK cachers?