The placement of compliant material between tank & stand will allow for some equalization of uneven contact & any uneven forces that result from that.
The problem is that glass is known as a high modulus material (modulus = stress/strain, in physics).
That means it does not respond well (think 'deflect') to uneven forces or sudden changes in applied force.
A rubber ball or spring, for example, typically have a low modulus.
I purchased a large sheet of the rubber that is used under Innovative Marine tanks, for my build.