Jeff, that's not a bad theory. A good way to test it would be to see what type of clamshell the Grievous exclusive gets. Since Target tends to be the only brick & mortar that gets exclusives with clamshells, it would make sense for them to want to protect against figure swapping. Granted then that gives them justification to bump up the costs, which hurts the honest buyers.
The Target Grievous has a taped sealed clamshell...
JD 's Target Grievous Image