I agree that's good advice, but I think the average person heeding that would reserve a Tahoe or Suburban (say for a ski trip) without realizing that Chevy sells those in both 2WD and 4WD. Me, I'd feel fairly confident that National would have a 4WD for me, but I'd have a backup plain just in case. The downside to a backup plan is zero, the upside is potentially huge.