Definitely I'm going to have dauer kicked out over this...deceitful hiding of his mod status. Of course, I could overlook it if he were using an appropriate title such as 'Cookie Monster'. That's definitely a mod name. Cookie Monster.
Shabbat is Friday at sunset to Saturday at nightfall, not Sunday, and to answer your question, none of the liberal movements are terribly authoritarian so it comes down more to the obligations an individual accepts upon him/herself. There is no religious question that I could answer by stating either, "It's allowed" or "It's not allowed" because that is not the way I do religion. I could however say "I do this" or "I don't do this" in terms of my own personal practice and give explanations for why.