Although the WTFPL website (http://www.wtfpl.net/faq/) does note somewhat ominously that it hasn't been tested in courts, it seems legitimate enough to me. Is there any evidence outside of its lack of history in court that would indicate it isn't suitable for production use?
EDIT: gnu.org also says "We do not recommend this license" ,pointing to the Apache license as providing better protection against 'patent treachery'. (https://www.gnu.org/licenses/license-list.html)
EDIT: gnu.org also says "We do not recommend this license" ,pointing to the Apache license as providing better protection against 'patent treachery'. (https://www.gnu.org/licenses/license-list.html)