How many grandmasters have been stripped of their grandmaster titles? I heard about a GM in the bathroom who had his taken away, and was wondering what other circumstances have resulted in a GM losing their title.
After doing some checking, it seems that this is a relatively new phenomenon. Before the advent of technology, and strong chess playing programs on smartphones, it does not appear that any GMs had ever been stripped of their titles until GM Gaioz Nigalidze, at least that I could find.
Gaioz Nigalidze was stripped of his GM title after being caught with a phone in a bathroom stall at the 2015 Dubai Open. He had been suspected for some time.
The case that you probably read about was GM Igors Rausis. Last year, Rausis made international news when he was caught doing the same thing in a bathroom stall at the Strasbourg Open. His behavior and meteoric rating increases over the course of 6 years had put him on the radar for a long time.
This seems to have set a good precedent as far as I am concerned as there is no room for cheating.
P.S. I found this interesting post that, believe it or not (at least in the case of Nigalidze) claimed he could earn the title again if he completed the norms in the future; but the official FIDE ethics report does not mention the possibility either way.