Sorry, I should have been clearer. I mean upstream third party packages, not those that form the core of Debian itself. If I create a package which Debian ships unmodified, but it's then subsequently patched by Canonical and shipped with Ubuntu (or via its repositories) under the same name, I'd argue that I could (but possibly shouldn't) cry foul as Canonical are doing with VPS providers.
By uploading it to Debian I think you have to accept terms to match the rest of the system. You have to object at the source; once it's in Debian, then any downstream developer can do anything he wants with it, as long as it abides to Debian licensing terms.
If you don't accept the Debian terms, your package ends up in "nonfree" and I honestly don't know how that is managed downstream.
