There ought to be a way to uninstall, if for no other
reason that it is polite behavior in a civilized society :)

The usual way to uninstall something from a "package"
seems to be to keep a list of all installed files
somewhere. Doing the equivalent of a "find . -print" at
the right point during "bdist/build" should do the
trick, or maybe a command of its own, the filelist to
be stored in the sdist-result?

Such a list of files would also be useful for
packagers, be it maintainers of .rpm, .deb or *BSD ports.