So if I killed you and never got caught, it wouldn't be illegal? Ok, thanks for clarifying that. In that case, I suggest we drop the whole issue of opt-outs. If there isn't any legal reason for doing it, then we just shouldn't do it. It's far too complicated to do purely in order to be nice. (If you know of a simple way to do it, please do speak up.) Consider this scenario: 1) A French resident adds something to Wikipedia, under the current GFDL (They don't need to be French, but they need to be willing and able to sue in a French court, so it's easiest to assume they're French.) 2) Wikipedia invokes the "or later" clause and moves over to a later GFDL 3) Someone else edits the article, with their contribs under the new license 4) Another French resident tries to reuse that article. As far as French law is (apparently) concerned, the initial user's contribs are still under the old GFDL, so whatever the person in step 4 tries to integrate the work into has to be under the old license, yet it also has to be under the new license to be able to include the contribs added in step 3. You end up with the reuser having to have parts of their new work under one license and parts under another, which is very confusing, very difficult to keep track of, and also possible in violation of the GFDL anyway. (The WMF actually has the same problem, but doesn't fall under French jurisdiction, so it's not an issue.)