Cars did have this a long time ago. School buses had it up through the 90's at least, and firetrucks will probably always have a kill switch due to the potential of taking in combustible stuff through the intake.
Honestly I'm fine with using a key, it's good UI design to have an e-stop system that the user can operate without doing anything special or unusual. The only real danger is how easy it is to accidentally engage the steering column lock at the same time (or overly aggressive anti-theft systems that kick in and leave you dead in the water with no exterior lights...)
However I really don't like the new keyless systems, if I hit something and there are flames pouring out of the engine compartment and I can't get out, I'd much rather physically cut power to the fuel pump (and disable HV on a hybrid) than hold down a button I've never used before for a few seconds to send a request to a likely damaged controller to pretty please start the shutdown sequence.
Honestly I prefer a little bit of white noise from fan turbulence over quiet electrical noise, without something to drown out the PWM noise I'll occasionally wake up in the middle of the night thinking I have a failing capacitor.
Perhaps that's a sign that I've spent too much of my life messing with electronics.
Supposedly when my grandad got a 3-day weekend, he would "visit" Texas -- starting in Seattle, passing through California for the heck of it, and making it home in time for work. He had a massive Cadillac that got 13mpg at any speed, so he'd set cruise control for 110 and drive until he had to pull over and take a nap.
I don't know how much of the story is true, but I guess roads were way more open back in the 70's, gas was cheaper, and we have pictures of the Cadillac...
Yesterday I installed the latest version of Skype on my laptop. It turned on my webcam, took my picture, and tried to set it as the profile image for my Skype account.
Of course, it's crazy to expect to be pseudonymous on skype but that was still a little unsettling.
You can tell pretty easily from the MAC address, which is broadcasted in the clear even on an encrypted network. You *can* change that on most routers, but most people have no reason to.
Mine was "linksys" for a long time -- not actually the default on my router but it was an open network and I figured most people's computers would already be configured to automatically connect to it.
Now I live in a denser city, everyone secures their networks here and if you don't you'll be hammered with torrent traffic all day.
No, your laptop by itself couldn't, but the protocol is certainly capable of handling the distance if you tweak the timeout settings and have a powerful radio and a good antenna setup.
They probably wouldn't actually use wifi though, some of the cellphone-based standards are more suitable for this type of system.
To use this you would probably need an antenna and modem set up on your house, much like satellite Internet. It would still be a challenge though, I've streamed data off a balloon before and we were tracking it manually with a high gain antenna and used extremely slow data rates. They're going to be limited to solar power too, which limits their radio output power a lot.
I only noticed jitter once or twice. It was less severe than jitter I've experienced through normal cell connections (and even on landlines), although I'm sure it could get way worse with bad network conditions.
In any case, that phone is broken and the carrier doesn't offer any UMA-capable phones for almost free with a contract anymore. I don't like talking on the phone anyway so meh.