Plenty of software will kick you from servers or even kill the game process if they detect anything, including false positives like some suspicious string in a completely unrelated chat application.

Who cares though? Fine, you can say they monitor you. The point is: to monitor you, they gotta pwn your machine. If they don't you can just defeat their silly "monitoring" software. They own your machine by installing kernel mode malware into your OS. They literally rootkit your computer.