I have just been doing some research on contestants on Come Dine with Me. Turns out one competing hostess who required shoes-off was Tanya Williams in Edinburgh, a born-again Christian (go Christians!) from Texas serving southern state cuisine.
This contestant was black. I may be totally wrong, but I do get the impression that black people seem a lot less shy than whites in asking for shoes-off. I must admit I have never visited the home of a black person, having mostly lived in predominantly white areas.
Another contestant approved by this blog is Nikki Bennett in Birmingham, who requested that her guests remove their shoes and bring slippers with them.