I let your previous comment (about inductive load kicks making it upstream to and through a wall wart with enough energy to matter) go by because I'm basically a pleasent kind of guy, but c'mon now. ... pure sinewave output. ?!?!?
I double-dog-dare you to justify your implication that an UNPURE (!!!!!) sine wave AC source will have any negative effect on the effectiveness of most Zapper circuits.
Unless, or course, it is a problem for SOME manufacturers..........??????????