Here's something that may help others. If an employee unfamiliar with the promotion tries doing it, they'll likely start trying to look up trade in values for your games. This is not the way to do it, as we know, since people have been trading in super old games which would definitely not be...
FYI, bought 1 and left 1 at Coronado Mall Kohls in Albuquerque as of 1:29PM MT. Customer service associate found it in the system by searching for: 3DS bundle.
Multiple copies probably depends on the associate conducting your trade-in. I was able to apply the $10 bonus when trading in AC IV, BF 4, and CoD: Ghosts yesterday for $160 total.