In images you can add a statement like that in the lisense but not in normal wikipedia. If an editor beleived that once his edit was on the wiki server it was no longer his (copyright) but part of the world and beleived that he had reliniqushed all rights would that class as a release? Although essentially he misunderstood his rights, does this kind of tort have any validity in US law?
No. I release would be someone writeing something along the lines of "I release you from the requirement to credit me for this work"
Of course such a stamtent may not have legal force in all countries.
-- geni