i remember tricking the website when i was a NW elite, and the CO site didn't recognize NW elite status yet. (i posted my method, too, so you should be able to find it with search..) once i got the seat, it stuck, because the main CO res system recognized my status.. it never worked for exits, tho -- it would change the selection on the web page to show me in the exit seat, but hitting continue or selecting the next flight would return an error that the seat couldn't be assigned. (the fact that i couldn't get a seat i wasn't entitled to made me feel alright about posting the method..)

edit: i just tried a dummy booking, and was able to grab 5F on a 737 without any status at all, using the same method i posted here in 2002. i didn't buy the ticket, so i have no idea if it would stick long term, but i got through the seatmap, and checked expertflyer, which showed the seat occupied.