How reverse sidebars work. 

I said it's unpickable *in theory*. In practice, you'll find many pick and gut videos on RU-vid where people exploit practical vulnerabilities. So with that for context, these are just another flavor of high security lock and they aren't ubiquitous for the same reason that the other flavors aren't ubiquitous: they're expensive and the cost can't be justified for most applications.

Other than the Gen 3 Smart key, the first ones that come to my mind are the famous Yuema 750, and a fair number of automotive ignition locks. Here's a cool video that describes the Yuema: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-jWPbDRnzkmQ.html

Briggs and Stratton General Motor car locks, 1936 onward. (and the term reverse side bar is not what they are, it's a made up term)

It doesn't seem too hard to make the bar *inaccessible with a shim* 🤔