Some laptops already have physical switches for wireless connectivity, couldn't you just add one of those that cuts power to the onboard microphone and camera?
At work, two of our users have Asus notebooks (I forgot the model, though) where the "On/Off"-switch for the camera just moves a piece of plastic in front of the lense. Maybe it also turns of the camera, but once the lense is covered it doesn't really matter any more. I like the idea, and since it must be rather cheap, too, I wonder why not more companies do this.
If you buy the business version of my webcam you get a plastic cover for $2 over the cost of the consumer variant. One day I might spend $15 for a cover: http://www.amazon.com/dp/B00I005TPS
On the one hand, for a price difference of $2, I would go for the version with the plastic cover.
On the other hand, with an external webcam, I can simply disconnect it. If you have a laptop built into a laptop that is not so easy to do. At least, you have to trust the laptop's manufacturer to do that, while a builtin plastic cover is so simple one does need to "trust" it; at the same time, you can't retrofit it on a laptop... :(
That is already out there too, with Purism Librem laptops.
The commenter you're replying to would be better off giving his money to a company that puts privacy (and FOSS) above all else, instead of trying to bribe a lost cause (let's not forget about the 3 times Lenovo has been caught with nasty factory-installed malware on their consumer laptops).
Purism is a joke - they rely on binary blobs like everybody else. It's an overpriced laptop with a fancy marketing campaign - might as well buy a Lenovo.
Some Lenovo ThinkCentre all-in-one PCs have a physical sliding webcam cover, and you can see at a glance what position it's in. Microphones are harder to handle in such a low tech way, though.
Shorting the two wires of the mic together with a low-value resistor will do what you want, or you can have a physical disconnect switch. It's very easy to modify a mic in this manner if desired. You can even have the switch built into the sliding webcam cover. On digital mics it's a bit more complex to mute without disabling, but the brute force solution is to disconnect their power line in the same manner. Then again, you now have to watch out for things like accelerometers in the board or hard disk which can reconstruct keypresses or act as a very low quality microphone.
That last point is interesting. Even with an RF detector, an accelerometer may act as a cheap room bug. Heck, if automobiles use them to detect when an airbag should be deployed, why not just use them as bugs in cars? Now I'm scaring myself.
Heck, if automobiles use them to detect when an airbag should be deployed, why not just use them as bugs in cars?
AFAIK the airbag accelerometers are designed to detect much larger accelerations than e.g. the ones in a smartphone, and are thus essentially completely insensitive to anything lesser than a huge impact -- spurious airbag inflation is one of the things the manufacturers really, really don't want to happen.
Many of them are just mechanical switches actuated by a weight, with no active electronics (makes sense for such a safety device to be as simple as possible): https://www.youtube.com/watch?v=mWSlwhYyOhI
And even when not impacting anything, a car is not exactly a quiet and vibration-free environment either...
Personally, I am not worried about quite sophisticated attackers. When securing my house I'm worried about run-of-the-mill burglars, and this is like that.
