I've never seen this done. I'd love examples for companies. Social media often augments folks, but I've never seen someone rejected for not having a LinkedIn.

That's as silly as companies that only look at your Github.

I.e., I'm sure someone out there does it, but they are dumb.

A company I worked for started outsourcing a lot of its work to a certain Asian country last year. One of the issues we had when trying to recruit people is that they will just blatantly lie about their experience on their CV. Asking for a GitHub profile was an easy way to backup their claims, with minimal time wasted on my side - at least until they cotton on and start putting fake projects there.

(Admitidely trying to outsource work just to save money was dumb, but it wasn't my decision, so I had to make do)

Which companies are those? I've never had a problem getting jobs and interviews without a linkedin account.