I honestly think GM didn’t realize so many of their lease incentives were stackable and only recently has cut back on them. They also didn’t realize us hackrs knew how to get the unicorn deals from them, and then this forum began to grow and spread the news.
I recently encountered this too – interest rates have risen. Take the demo. If it makes you feel any better, the 2019 is light years more superior to 2017 you’re dropping. Well worth an extra $50-60 a month, imo.