I posed this similar question awhile back as to why Type SE was allowed to be used but not Type NM. To me a bare wire being used for neutral is a bare wire being used for neutral. One of the replies that I recieved from Joe T. was that the CMP just decided to draw the line somewhere,with no given explanation . It's a d**m shame they couldn't explain their reasoning a little better.
[This message has been edited by txsparky (edited 04-09-2003).]
FWIW, in Canada, the code, as far as I can remeber, has been to install 3w+G to range/dryer installations. I have only seen the outlet type associated with 3 prong ranges used for old 220V/50A welders.