Believe it or not, I've never received an ECV, but I for one have a tough time believing it can't be used to buy a ticket and upgrade it.

After all, what's stopping you from verifying that there is "R" space on a flight by phoning NWA, and then using nwa.com to buy a economy ticket in the appropriate class (remember, non-elites can only upgrade with miles on certain fare classes for domestic travel), thereby using the ECV, then phoning nwa to do the upgrade?

If this is against the rules, it should specifically be listed in the terms & conditions of the ECV.

I have used the old TCVs for the same purpose before as well.

Please post any response you get back from nwa!