> It uses more real estate than a pure switch, but requires no open holes through the case.

This is at odds with the (apparent) consumer preference of smaller everything.

> The easy way to ensure that a switch is waterproof is to use something like a magnetic reed switch or hall effect sensor,

Um, using a hall effect sensor is exactly the kind of "soft switch" we're trying to avoid, no?

And magnetic reed switches are big, very expensive, vibration sensitive and failure prone. Since this is security, you're going to want it to fail open and you're not going to want a switch that closes briefly if you vibrate the phone.

Mechanical engineering is hard. Let's go shopping! ;)

What's the difference between a hall-effect sensor + transistor that the manufacturer promises is a hardware off switch and a hardware switch with inaccessible contacts that the manufacturer promises is a hardware off switch? Either way, the consumer is going to want a light or other indicator that shows when the camera is in use.

Reed switches are available that are a few mm long, they aren't exactly huge.

Let's go shopping ... for a metallic surgical implant for our index finger so we can operate the hall-effect-based camera/mic on-off switch. :)