I had an issue with alignment shop on my daily driver (not my 1LE) I was eating tires. Horrible wear from center to inner treads , it rang true that the technicians were not tightening things up and it was walking. It took me 3 times and a set of front tires worn.
As mentioned a good alignment shop is key and checking the alignment every 6K on the daily. The 1LE has been checked right around few times and it did walk but that was with track use and driving on the twisty.
Actually just purchased another set of Goodyear OEMs for $730 from Tire Rack. They posted that they were 2015 production.. but hey that is fine with me. About to start hitting up the tracks again.
OP glad to hear your getting that discount from Costco for premature wear. They are pretty good on their tire pricing..