how to conquer random mac address?

RouterOS General
11

Hm, I managed to make a script that is triggered on DHCP lease

{
   :log info "DHCP trigerred";

   :if ($leaseBound = 1) do={

      :log info "Lease Bound";

      :do {
        :local Comment [/ip dhcp-server lease get value-name=comment number=[/ip dhcp-server lease find address=$leaseActIP]];
       }

      :local FirstByte [:pick $leaseActMAC 1 2 ];

      :local FirstByteHex "0x$FirstByte";

      :local FirstByteNum [:tonum $FirstByteHex];

      :local StatusBytes ($FirstByteNum&0x3);

      :local MessageText "IP: $leaseActIP MAC: $leaseActMAC Name: $"lease-hostname" Comment: $Comment";

      log info $MessageText;
      log info "First Byte: $FirstByte $FirstByteHex";

     :log info $StatusBytes;

     :if ($StatusBytes = 2) do={
        :log info "Random MAC!!!!";
     }

    }
}

I guess the rest should be easy: to change lease to static, add comment and make it block access.
Ideal would be if I can inform client that he is not allowed to use random MAC but it seems quite complicated to do.