I've just noticed a lot of people posting accidentally as Anonymouse Monk and then following it up with another post lamenting the fact that they forgot to log in. Since I use the dark theme, I never have that problem. It just seemed like a cute idea to use the sites ability to change look and feel to reenforce the state of the user with a little change in color.

> ...red -- it would have seemed very confusing,

Would green be better?

> the lack of voting radio buttons,

New users don't see the radio voting buttons since they can't vote yet.

> preserve the "element of least surprise"

The fact that users so easily confuse the state that they are in seems to go against that rule. Using color to reenforce state just seemed like good UI design to me.

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