Fair enough, but I would tend to say that the time to worry about that is *before* you post a story publicly, not after. There are so many ways a webpage can be archived, up to and including printouts by others, which can make their way into other hands. Once you've released your writings into the wild, it's dangerous to assume that you can ever call them all back. You can wipe away some of the footprints, but they'll probably never be all gone.

And I cannot possibly fault those original creators who prefer that their carefully crafted characters not be pulled this way and that by those who had no hand in the genesis.

To be honest I am a bit surprised to hear you express this opinion, given how vigerously you usually defend fanfic as a literary tradition. The idea that a writer "owns" their characters, even those that they've invented, is a fairly new one, and I'm not sure it's a particularly useful way of looking at a creation. Do you see a difference here?