Does anyone know how exact the "free weekend day" coupons work? I know it doesn't get applied until you return the car, but the coupon requires a 3 day rental. So, what happens if I return my car at 2 Days 22 hours even if I reserved for the full 3 days? Can they somehow opt-out of honoring my coupon? Thanks!

http://www.costcotravel.com/#ap_rent...UGZ50320080325