But then, is anything free? I mean, if they say "you can do with it whatever you want", they can later claim rights. But how is this different from saying "you can do this and this and that but not that"? Why would the first be revokable and the latter not?
By the way, this is actually a point against the GNU/FDL too. According to Dutch law, I cannot waive my right to disallow changes to my work. So technically speaking I am not able to give you the rights under the GNU/FDL. I can only allow republication as is, or with modifications I explicitly allow.
Andre Engels