Originally Posted by
KRSW
You'd "connect" but all packets/traffic would be blocked.
That's not entirely accurate. MAC filtering would prevent him from getting an IP address from the DHCP server, and if he was unable to get an IP address than his laptop wouldn't show as being connected to a network.
And like you said, if someone is too "lazy" to configure their router (ie., they're broadcasting the default linksys SSID), than it's unlikely that they've configured MAC filtering