I half-agree, Chuck. It's like a steering wheel clamp. If a thief is determined to steal YOUR car, they'll do so whether it has a steering wheel clamp on or not. But if they're just looking to steal ANY car, they'll choose one which doesn't.
Similarly with MAC address filtering. If a determined hacker has some reason to bypass YOUR security, they'll do so in a matter of minutes. If, however, they're just looking for any wireless network to jump on, they'll find one where they don't need to go through this additional step...