@chasm99,
Good information. I imagine they get away with it because most people don't do their homework. It's also possible Budget has a wider network area.
I did once get the inside skinney on U-Haul vehicles and trucks. If you are moving to a town with a high percentage of college studends, and doing it at the end of the school, you can get a good rate because they are using a higher than normal percentage of vehicles to move out. Try the same trip at the beginning of the school year, and it will cost quite a bit more.
On car rentals, I have done much better with Dollar than Budget when renting comparable cars. Notice that when you turn the car in at an airport, and your flight is leaving with or without you, you are not in a strong negotiationg position.