Hey @tj_hudson 
All of :r: cards are contactless and both the standard and the premium will work with the premium account. No real difference apart from the exclusive design.
Correct. The loophole would be sending free expedited cards with a free trial that people could cancel freely: everyone would subscribe to the trial and then cancel to get the free shipping 
Keep in mind the premium card, according to the TOS, will stop working if the premium status is lost 