I still don't see the problem. If you dual license Wikitravel, your authors will have no direct disadvantage whatsoever. It's just another sentence on the article submission form. Both licenses grant derivative rights.
i just wish everything was public domain. I really don't like licenses. i really see no point for not making things public domain.. that is TRUE freedom without the viral side effects of GNU licenses. or commercial restrictions of others. i really never understood that part, i think it really limits the uses of all that content / source.
I really wish wikipedia had used the public domain as a license. therefore everything would be able to be used everywhere.
Lightning