Butler has not raised the threat level on anything. This has been a widely known issue since forever. A friend of mine wrote a sniffer that could do this back in college, and he was one of the last to the party. Want something else to kvetch about? His tool could impersonate the router and act as a proxy, including serving up ssl-encrypted pages to users who didn't realize they shouldn't accept certs from unknown signers - again, that was years ago, and even then it was nothing new or unique at all.

When a tool like this rises to even a minimum level of public consciousness, you're better off thinking "people have probably been doing this for close to a decade" than "this asshole just ruined the internet by pointing out an obvious flaw that someone will now be able to exploit".

And yes, at some point, a door manufacturer that knows how easily their doors will open and how frequently people will just walk through does take on some responsibility to add a lock (and the homeowner to use it). It's going to cost more in servers? Okay, so what? It costs more to install seatbelts, are you upset at Ralph Nader, too?

[Edited to bring it down a notch]