[markszcz]

I'm interested to know, or know the theory on to how the developer came about to check if GMod was pirated.

I agree with what he is doing but is there a way, without a shadow of a doubt, always be able to prove it was pirated and not a legitimate glitch?

[devicenull]

He sends the user's steamid (a unique identifier of the account) back to one of his servers. Presumably, that server compares it to a list of people who have purchased the game. There's very little little chance of a false positive. The check will not crash the game if the server is unreachable (which the pirates have already discovered), so it won't turn into your usual "DRM servers are down, can't play my games!" issue.

[markszcz]

Thanks! I was going to ask for a link to how you know this but it makes total sense. I was already thinking if that was the case or if something else was being done but going back to the servers is the most logical explanation. What personal computer isnt hooked up to the internet these days. The game must have come from somewhere, most likely the internet and not someone’s floppy disk/zip drive/usb stick.

[markszcz]

A little bit more of an explanation of the error and consequences: http://gamrfeed.vgchartz.com/story/85554/garrys-mod-creator-...

tl;dr "Reports were ... flooding in about an error message upon booting up Garry's Mod which reads "unable to shade polygon normals" followed by a bunch of numbers.

The thing is that those numbers that appear after the error is actually the user's SteamID. ...The SteamID...has allowed for easy permanent ban distributions"