A recent AP story talks about the increasing number of children dying after being left in sealed cars by mistake. As a society we have 99% of the infrastructure necessary to prevent this. Most newer cars have an alarm system and automatic climate control. The alarm system implies a vibration sensor, a microphone (for glass breakage), and a little computer that is up and running all the time. The automatic climate control implies an interior thermometer.
With a bit of programming the car can recognize that (a) someone is inside the car making noise and moving around a bit, and (b) that the temperature is climbing to an unsafe level (or getting too cold in the winter). Now what? If we had a wireless Internet for the price of $3 in chips the car would be able to send an instant message to the owner and the local police to come back and check the car. (Of course you could do this now if you wanted to buy a $300/year cell phone subscription for the car, which is essentially what the GM OnStar system does, but most people wouldn’t be willing to pay the extra $300/year for something with such a low probability of ever being used. Hence the need for a better national infrastructure.)
In an age where we spend infinite money and effort on high-tech cures that save a few lives it is a shame to see kids dying for want of a few lines of software and a $50 802.11 base station.