Ken, not to say your opinion is wrong, but you seem kind of over confident in your assumptions.
The U of M's snake room is a uniform, constant temp and humidity and they have burms, bcc, garters, corns, kings, bulls and a few turtles all in the one room. One of the bulls they had reached the unbelievable age of almost 30 in those conditions! Itís kind of hard to dispute that evidence.
But, in the wild snakes do seek warmer and cooler temps. That much is a known fact. Maybe it's because of the extreme variables in temperature in some climates. Maybe it's because they "need to". Maybe it's just how certain snakes live in certain environments? Who knows?
I think it would be cool if you raised X# of snakes in one type of room and X# in another and see which group does better over the course of 10 years or so. That's one way to get your answers. Merely saying that your snakes have done fine in those conditions for so many months is just too inconclusive to be making such strong statements. If they are only offered one temp, why would they cruise to look for another temp that isnít there? And the water would be the same temp as the room. It might "feel" cooler, but it's not.
I keep my collection with a heat gradient and almost all of them use the different temps available to them. Some sit on the heat a lot and others next to never. I see those differences among the same species. But I like to offer them the choice either way.
Good topic though...