well, i've found that Gold rentals seem to be printed with a time a bit later than my stated pickup time. if i show up while the car is still in the stall, i get that pickup time. and with a one-hour grace on return, i often get 25-26 hours out of a one-day rental. showing up six hours late wouldn't work, tho--once the car is out of the stall, they'll print a fresh contract when you get there, with your actual pickup time.