This appears to be a news article, but it's got a strong slant towards monitoring: The article presents a sensational opening! Child porn being downloaded! A warrant! Pounding on a door! But it's only an elderly lady, and she's not even stealing music. No, we get the specious fact that the police are powerless to apprehend a villain because the elderly lady is fiendishly operating an unprotected Wi-Fi access point. "Perhaps one of those neighbors, authorities said, was stealthily uploading photographs of nude children. Doing so essentially rendered him or her untraceable," the reporter writes. Not so much: Traditional police work coupled with an exact geographic location should have provided enough clues.
But apparently open Wi-Fi is a huge danger because this reporter hasn't heard of anonymizer and randomizer services that allow anyone at any public terminal--Wi-Fi, college campus, or even, gasp, at a workplace--to be used in a fairly untraceable manner. In fact, probably more untraceably than hopping on a free or open Wi-Fi location and abusing it, assuming security through security.
This quote is rather telling in the same manner: "Unsecured networks are a treasure trove for neighbors," said John Sheehan, program manager of the CyberTipline at the National Center for Missing and Exploited Children. "Those looking to access illegal content obviously feel they have anonymity" and can get away with it.
Again, if neighbors are gaining access, then it's easier to trap those neighbors through monitoring. They may "feel they have anonymity," but they have quite a bit less because of proximity.
And here's a nice piece of opinion right smack in the middle of the article: "Open wireless signals are akin to leaving your front door wide open all day -- and returning home to find that someone has stolen your belongings and left a mess that needs cleaning."
No, it's more like having an endless pot of coffee that you're willing to let anyone pour a cup from, even though you're paying for the electricity. The coffee is essentially free, because you're paying a fixed amount for unlimited java. The "front door wide open" argument applies when you intend to close your network and fail to; don't understand that your network can be closed (and if you did, would prefer to); or you're an incumbent Internet service provider arguing that bits aren't bits: one set of bits must be paid for differently than another, and sharing access is theft.
(I don't think that every ISP must allow sharing, and I do agree in following the terms of service agreed to. But given that the terms for broadband are essentially coercive due to the effect in the US of having no nondiscriminatory access by competitive providers for wireline access to homes, that means that the market hasn't decided that not allowing sharing is a reasonable way of doing business.)
The reporter also notes, "Closing cases is more difficult if the IP address originated from a wireless signal because it often leads back to the owner of the network instead of the criminal." That's only true if you're thinking about abusers has working from single locations. The writer notes that with an increasing number of open access points, the problem will get worse. Again, that assumes that you have thousands of people roaming across extremely wide areas to gain access. It's more likely that people act within a relatively small distance from their home, making a pattern of abuse easier to track down: "Hey, that guy downloaded child porn here, here, and here, so he probably lives about here."
The interesting point here is not that this story is biased towards a particularly naive view of law enforcement or the idea that there must be millions of people engaged in illegal activity over open Wi-FI networks; nor that open Wi-Fi networks are de facto bad and/or unintentional; or that this story has been told better, with greater balance, in other publications over the last couple of years.
No, what's interesting is that more and more home networks are being locked down. In informal and formal surveys by myself and companies involved in monitoring this sort of activity, an increasing number of home networks are locked down with strong WPA security, making them more or less impenetrable to even determined access. (WPA isn't perfect, but it takes a fair amount of effort to break a weak WPA passphrase--too much effort for a casual "anonymous user.")
So I would have cast this story as--how will law enforcement adapt when people can connect from anywhere at high speed and get on and off networks fast? How will individuals and companies who want to share access, whether from home or in a coffeeshop or even at an entire airport (Las Vegas, Phoenix, etc.) cope with law-enforcement demands? What's the rate of change for securing home networks against easy access? Those questions would probably have interesting answers.