Re: Surely a sensible plan is not THAT difficult?
There's also the issue that knowing a MAC can lead to a masquerade or other lower-level attack. It's one reason IPV6 had to be altered as it wasn't considered from an adversarial POV.
Only by an attacker on the same local sub-net. And anyone with that access would be able to gather all the MAC addresses using a simple packet-sniffer.