Watch: I choose to ignore the warranty clause per clause 0. Also, since that clause exists, I can choose to apply it to other code I combine it with (unlikely, but its a dumb license that way)

Past that, I'm not convinced that due to clause 0 that it can be combined with other code, and I am of the opinion that more licenses are not good for open source development in general.

A responsible coder, given the desire in the wtfpl, would adopt a richard hipp style posture, or choose mit,bsd or apache.