I have a Wifi card in my Jeep because at work we have 3 locations that are open and I have access to all three locations. I would be nuts to pay when I could use it for free.
As well I update my machine and my files at home while sitting in the garage. I dont need on the road internet access because I have a cell phone that has web access and a browser so I can check my email without my Jeep too.
As for all that Mac filtering stuff. Sure hack my system and use my wireless. I just hope you know what MAC addresses I have allowed and what computer names I have set to allow. Its not that tough to setup. Basic security goes along way.