While David Brevik did move to GGG, he is not a dev there. He is an “advisor” and was originally hired to oversee their product exportation to China. Now GGG founded their company making games on the D2 engine, and were big fans of it, but I am pretty sure Brevik is the only D2 team member that went over, and he isn’t a dev there, at least not fully.
I mean programming in methods of anti-perving the camera view have been common in games for decades now.