I have long taken the time to set a mac address filter in my wireless lan just to make it next to impossible for someone to gain access to my wireless lan since I only put mac addresses of trusted computers in the list. Recently, I told someone what I did and he said - Well, what is to prevent a device from listening to arp broadcasts and then spoofing one of those. That would defeat your mac filter, wouldn't it?
I thought it was a good question so I pose it here to those that know more about how wireless works to "discover" devices on the network. Could this be done? Have there been reports of anyone doing this?