At my old dojo, an orange belt was for 4th kyu. So when I first joined my new dojo, i wore that belt on the first day... kinda hoping that I didn't have to start from the beginning. Everyone was staring, but I didn't care. It didn't affect me at all.
Till later I found out that they weren't really bothered that I already had a kyu grade. To them, the test of that is on the mat. They just found it funny that I was wearing a child level belt (8th kyu) for their dojo, and some of the children later told me that i looked really old for a kid.
I was told all this when I retook my 5th kyu again, by sensei with a real straight face.
Moral of the story: Go to new dojo, put on white belt.