I almost always carry extra stuff with me to fix full or wet logs or the like. Astrodav is right about not changing someones cache, but I know that when someone replaces a wet or full log for me, instaed of posting a "Needs Maintenance", I very much appreciate it. Ron White even went so far as to replace a bison tube O-ring for me last week! That's awesome!
Another thing that I have done on occasion, is to replace one that is obviously missing. That doesn't happen very often, but when it even says it is a skirt lifter and it isn't there, I would go ahead and replace it, with the knowledge that when I notify the CO that I did that, they may ask me to delete the found log. It has never happened that way, but I know it could. I know WAAAY more cache owners would be appreciative than not, so I usually go ahead if I am SURE.
Hope my 2 cents worth is helpful.
Guess what?! I got a fever, and the only prescription...is more cowbell!!