I too splice all conductors, UL listed or not. Personnal quality / prefferance. (Not saying that those who do use the device terminals perform lesser quality work.) But I would have a kiniption if one of my guys does it, as I feel it sooner or later may become a call back for warrantee. And, I would defininatley hit the roof if it were done on a 3, or 4 wire circuit. This could subject the circuit to under/over voltage should the neutral fail. And, that may also be a code requirement for the 'grounded conductor', as well as the 'grounding conductor'. (I'm on my other computer and can't check now.)
