True, but this is probably enough to stop quite a bit of piracy. Any program that has the capability to modify the binary of an installed program runs with quite a lot of permissions. Since it is also illegal, average joes don't have a trusted source for the patcher. This means that the only way to break the game is in the form of an executable that is functionally indistinguishable from malware. That alone will stop a good fraction of piracy -- plenty of people who would be willing to rewrite some hosts file to point to a fake server are unwilling to run a crack program that came from PirateBay and probably has keyloggers, spyware, or a rootkit.