In an interview on IGN.com Rockstar noted that

In the seemingly inevitable event that some dirty pirate manages to crack GTA IV PC and make it available, what are the advantages and disadvantages to using a legitimate copy over a pirated one?

Rockstar: Aside from the fact that warez are a great place to pick up a Trojan or key logger, using a cracked copy of GTA IV PC will result in varying changes to the game experience. These can range from comical to game-progress-halting changes.

Rockstar Games rewards loyal, paying customers and will offer incentives and downloadable content that will only be available to registered users of the game, running non-hacked copies, via Rockstar Games Social Club.

A reverse group calling themselves “fed0r” seems to have gotten rid of all trigger issues and the game runs just fine, so users of various torrent sites note. It only took 2 days with a 29kb file no less.

I’m really not sure exactly what needs to be done to really encrypt a file, but whatever these game companies are using now isn’t working, at all. I’ve done my share of reversing (with reversemes). There’s people out there that all they do is reverse. To understand a reverser, you have to sort of done it yourself. I have, and it’s highly addictive, even with just reversemes. I respect companies copy protections so I have never touched retail  programs.

I think game companies need to hire more reverse engineers to crack their protection, and then add code that will make that method not work.