I am of the opinion that the “cap” should only apply to tax deductable contributions. You should be able to contribute more, but not receive the deduction for the amount over the cap. There should NOT be any penalty for “stuffing” your retirement account.
I am also of the opinion that the cap should not apply AT ALL, if the total amount of the retirement plans is less than two million.
At the end of the day it does not matter what we think.