> Switches are very simple devices. If the switch mechanism is not enclosed, ...
Sarcasm, I hope? I spent an hour this weekend replacing some micro switches in some decrepit robots. These are about 5mm^3, which is pretty tiny, but huge on the scale of a modern phone. They are basically hunks of plastic with a button on one side and six or so leads coming out the other side. No, you can't open them up and see the air gap without destroying them. And yes, they are small enough to easily contain a full CPU, some flash memory, and a few sensors, even though they only really need a few sliding metal and plastic bits.
Sorry if I wasn't being clear. My point is that it is possibly to have switches that are easily verifiable. Most switches that exists are not because there is no motivation to make them so.
Sarcasm, I hope? I spent an hour this weekend replacing some micro switches in some decrepit robots. These are about 5mm^3, which is pretty tiny, but huge on the scale of a modern phone. They are basically hunks of plastic with a button on one side and six or so leads coming out the other side. No, you can't open them up and see the air gap without destroying them. And yes, they are small enough to easily contain a full CPU, some flash memory, and a few sensors, even though they only really need a few sliding metal and plastic bits.