Mmm.. I think this is not a real problem, because devices under 6LowPAN use a very low duty cycle, so they are using the channel only a few period, and do not collapse other devices. Wi-fi uses extensively the medium, but not the WSN.
"Itís not impossible to make these things work, itís just really hard..." Often it's not "hard" but "more expensive," meaning "more than someone wants to pay." I've peeked inside lots of RF boxes and asked myself, "How did this EVER get certified?"
An interesting side effect of this whole Part 15 thing, mentioned in the original article but usually NOT comprehended by the general public, is the "must NOT interfere with a licensed user" aspect. Someone who purchases a consumer Part 15 device that interferes with a licensed user of the same spectrum is required BY LAW to STOP the interference. This is often difficult to explain to a non-technically-savvy individual :-) It is really hard for them to understand that they can't use something they bought. It is difficult to get across the notion that the law protects the licensed user and not them with their (probably cheap) consumer-grade item...
My AT&T U-Verse gateway has ethernet jacks and wi-fi. I figured there was zero benefit to using wi-fi with my desktop PC three feet away, so I plugged in with a 2m Cat5 cable. Wrong! A thunderstorm blew in. I shut my PC down as a precaution, even turning the surge arrestor outlet strip off. A utility pole around the corner took a hit and my motherboard was toast. I bought a cheap USB 802.11g radio. As the EMC gurus say, only ground your system at one point.
I was thinking about this the other day. We used to use wireless communication to distribute signal broadly, as in a commercial radio station. Everyone seems to want to access this in a wired connection now, the internet.
Meanwhile, for simple point to point short range communication, we used to use a wired connection, as in from your CD player to your preamp. Everyone seems to want to use a wireless connection for this now, like from your keyboard to your computer. Interesting, ain't it?
I had a problem with interference from a cordless phone operating on 2.4Ghz. The Wifi router was set to auto channel, as there were no competing Wifis around that always meant the first channel. I set the Wifi router onto a fixed channel at the end of the channel list. Problem solved.
Now I am inclined to see how much disruption a leaky microwave oven can cause in some commercial areas! Of course, it certainly is correct to assert that wired connections are both more reliable and more secure, and now, we realize, they are more likely to be free of interference. The harsh reality is that for a huge realm of connections, wireless is a stupid choice, adding cost, complexity and additional power consumption , and providing only a marginal, at best, benefit. So here is the question again, that was asked a few years back, which is: "what happens when all of the channels are occupied?" How will the new toy work when all of the channel frequencies and all of the time-slots are already in use?
Of course, all of this is ignoring the question of what benefit is delivered by a toaster with an IP address. That is a separate issue altogether.