Just my imagination - hypothetical situation and won't actually consider doing given risk and ethics. Given how hard it is to clear Polaris upgrades these days, what if say you book a Y ticket and request the upgrade. You also 'block' 6-9 seats in J by booking fully refundable tickets using different names and hit cancel maybe 24-48 hrs before departure. Has anyone tried this? Based on trends, will the system release lots of PZ space or at least higher % of upgrades clearing (assuming those who were going to purchase the J seats would go to a different flight/airline). I'm guessing it's very high risk as if United denies the refund, you'll be on the hook for close to $50K in some instances. Also i'm sure it probably violates UA t&c but not sure if anyone has done research on this.