This is the first time I'll be using Costco's travel services to book a rental car. Costco says you may get a free upgrade on your car, but it sounds like it's pretty much up to however the person behind the counter at the car rental agency is feeling. I booked a fullsize car, which will work fine for our family, but it'd be nice if we could get the free upgrade to a midsize/intermediate SUV. Any DPs out there of how often/if people get the free upgrade?