They played it pretty stupidly, but maybe they have a way to blacklist the coupons that were send out by mistake. if you see that they ask 150 dollars a pop now and they gave them away for 19 dollars, for each unwarranted license they can block, they 'win' 131 dollars.
Then, there is also the marketing nightmare to explain people that they had no right to this coupon in the first place.