Azalea makes an important distinction.  To drop some of my gear at a site while I go prospecting for something better is very different from dropping off my gear with a clear intention to stay while I take advantage of the day and go off and fish or check out the lake.  The problem is that for the person coming upon the gear it is impossible to tell the difference.  Personally I would choose to believe the person is doing the latter rather than the former but to be quite honest its never actually happened to me and these days I'm tending to do my tripping in more secluded regions where it is most probably a non-issue anyway.  Philosophically speaking the answer is, as has already been pointed out, adherence to the Golden Rule.