If they're smart they'll require the minimum new purchase contract size to qualify.
They may do this, but then they may lose sales. I really think Disney is in the mode of maximizing revenue right now. They need to make a buck wherever they can to offset the rapid changes to the cable tv landscape and their cash cow (ESPN).
Eventually I think we will see a lot more upsells in the park as well such as premium viewing areas for fireworks, premium fastpasses and continued increases in dining prices, room rates and park tickets.
Also, I see them rapidly increasing their demand based pricing and charging extra for high demand dates. All the data they collect from magic pass allows them to make very accurate predictions about prices that the market will bear.