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