This is obviously an issue with Google Glass, but MAC address filtering is a waste of time. It offers absolutely no protection against a determined adversary. It is a perfect example of security theater.
From that, is simple to extract the mac address of an authorized client, configure your macbook wireless card with that mac address and join your unencrypted network.
This is why mac filtering is useless on wifi networks.
Expecting me to change my security to suit your needs is the height of hubris, when your device is not a necessity.
But mac filtering is a pet peeve for many of us. It is worth mentioning, as often as necessary: it's bollocks. Don't do it. Let everyone know that it's useless.
Read that post as if prefaced with: "On a tangent: ..."
We look at security as one would look at an onion.
Once someone has determined to break in, even minimally sophisticated they will spoof the mac address. It is good that you want to add extra security, but even as your story shows it just creates confusion, and make using the system harder.
Brittle outer layers?