Interesting isn't it?
I know an ex-copper who worked in the middle of Bristol. He stopped cars on a regular basis and often issued the driver with a producer. Part of that form consisted of a self titled race classification; the driver would be asked whether he/she was white, black etc., etc. On a regular basis he would get young black people classifying them selves as "n"!! Looking after his own back, he wouldn't write it on the form himself, so would ask the driver to write it then sign the form. He then made a Police notebook entry of what had happened!!
Nothing like making things easy!!