I also read a similar article today, and I think what they meant by idling, is something
to the effect of sitting in the parking lot and letting the vehicle run (especially
with the air on), while someone runs in to grab a pack of diapers or whatever,
for five or ten minutes. In this case, you would be better off to turn the vehicle
off and restart it. Or like in the old days, to let the vehicle warm up, as that is
not necessary with todays fuel-injected cars and trucks.