Or introduce some kind of validation in code, to block it from running from PC?
That DRM-like stuff has been broken every single time.
If you have the code on disk, you can also patch the code on disk.
With GTA 6, I really would not worry about this, given just how much interest there is in it. Someone will crack whatever they come up with.
...and that could all be avoided by not trying to cash-in twice by delaying the PC release by a year.
(To be fair though, I kinda do not expect it to be worth all of this hype. It is just more of the same from what I have seen)
Sony Rootkit II: Rockstar edition?