I haven't seen any announcement about them disabling the Serpent Tome system, which is the only true online/server side portion of the pass. I heard they removed the online pass from the UK PSN, but not on the US.
This leads me to believe that if you redeem a physical copy of the code, purchase a digital verson, or download the pass from the US that it will still work. As for whether or not that will be the case, who knows? They may shut it down, or keep it up if another company buys the rights.
The online trophy can be completed within 40 minutes of starting the game. So if you were to redeem the code now and get it out of the way ASAP, you wouldn't need to rush through the rest of the game out of fear of impending server closure.
I remember when hackers ruined the Gears of War 1 leaderboard. I had spent literally hundreds of hours playing it just to have my rank washed away. It isn't economically beneficial for companies to stop hackers from screwing up the games. Once they start to lose substantial amounts of money from hackers, then they will start to really combat it.
Leaderboards are never taken seriously anymore for just that reason. Most devs don't even remove them because it would be an endless battle. Not to mention if they banned every console that did it they would lose millions of dollars in the process. It's pathetic, but it's the sad truth of the gaming industry.