I think the rule is somewhere around these lines:
It's not wrong to RP a six armed guy, because that's original and could develop an interesting RP experience. But elves and robots are a CRB, because it's based off of OOC mythologies and it's too unoriginal (And, like Dudel said, robots aren't exactly humans).
Somewhere around that, at least...
EDIT:
rconley wrote: He may "believe" himself to have all those extra limbs, My character sees a plain man and I rp it as such.
rconley wrote:This is forcing others to "see" what his character "believes" when it is not something that exists in the game and that is the problem here. Along with (in my opinion) Knowledge this character had that there isn't any way he should have.
He also made the characters around him see he had six arms. So, your character would not see a plain man, he would be forced to see what the other player emoted. And that is that a man can have six arms. Now, if that's wrong? Someone from the PD should really answer us here, please.
"Delete Fu Island" activist.