I wouldn't say it's a one shot deal, but you're not going to be able to do it every year or even every other year.

Also, the comp usually isn't just based on status, but also flight activity, they want a copy of a statement that shows flight activity/miles to date/etc (when I got comped on US for myself and girlfriend, I printed DL's website, which shows activity for several months, including my GF's full fare Y ticket to LGW, which didn't hurt I'm sure).