I have a Rogers-supplied router and cable modem package, which twice has shown significant usage when I was out, once with the original unit and once with their replacement Cisco.  That makes me suspicious of the current state of authentication for wi-fi schemes (and I use the term "schemes" advisedly: they used to horribly leaky (;-))

What's a good approach? I have considered

• MAC address lists,
  
• no wi-fi (strictly wired doesn't work with solid concrete walls),
• a second router with a more secure protocol (is there such a protocol? And will my wife's Mac speak it?))
• something I haven't thought of
  

--dave

[The usage never runs me over my limit: I think someone is using me for downloads that might put them over their limit]

-- 
David Collier-Brown,         | Always do right. This will gratify
System Programmer and Author | some people and astonish the rest
davecb@spamcop.net           |                      -- Mark Twain