Hot Room

Why is the thermostat in every hotel room in America turned off when you enter, so that the room is insufferably hot and stuffy even if it is only a moderately warm spring day?  

If I recall my energy conservation tips from Reddy Kilowatt  correctly, wild swings in temperature setting require more energy than, say, keeping the thermostat at a reasonable compromise setting, like 72.  So why turn the thermostat off completely, causing the guest entering the hot box to curse and crank the dial down to Arctic temperature regions?

Does any hotel patron like coming into a room where the temperature is above 75?  Why, then, have the heat be the first thing that the weary traveler notices about the room?