Part of their thinking may be due to the way many tanks are built. If you look at the bottom of the tank, you may find the bottom glass is not really down at the same level of the outer edges. So no matter what stand is used, the center of the bottom glass is going to be floating. No problem for most tanks.
I wish you had been around a year back when I suggested that since the
tanks are built different, that rimless tanks need support under the whole
bottom of the tank. I have since just decided to wait till I see one only supported on the four corners like a conventional tank before I believe
that would be sufficient.
But at least a couple of the responses specifically stated that regular
tanks are built in the same way that rimless are and then it just gets a rim placed on it. They were at a loss to understand why I thought that would be a problem.
But a regular tank is NOT built like a rimless tank. It is plain to see that you understand this so I wish you had been there at that time.
Because I didn't know how to explain the difference to them.
But those Aqueon stands do have a lifetime warranty when the tank and stand are bought together.