Your premise is the rule is arbitrary and for such to be true you must define the word arbitrary like I have done previously and they make your case. FOR THE RULE TO BE ARBITRARY ACCORDING TO THE DEFINITION OF THE WORD IT MUST HAVE BEEN CREATED AND SUBJECT TO INDIVIDUAL WILL WITHOUT RESTRICITON; CONTINGENT SOLELY UPON ONE'S DISCRETION.
Now present your evidence that the rule was created thusly.
You see Mad Dawg, I am using the LEGAL definition which has been used in every Equal Protection case ever heard before the Supreme Court.
You are using a common dictionary definition, which explains why you are not a lawyer and I am.
Now go back to law school and next time PAY ATTENTION!