Well by reading a few stories (engadget, gizmodo) it looks as if the 2.0 software is already hacked, not even jailbroken but properly hacked firmware so that wont be a problem. As far as signing new contracts in store, yes i think you will have to. Apple know its fruitless to try and stop it being hacked so their only way to keep hold of it is via making sure people sign their contracts with the mobile operator.
What an absolute shame. I hear that there are also rumors that they may not go through with forcing activation in store (hassling you for it, but not forcing you), but when you put it that way, it does sound like they would do anything to stop hacking.
Damn it Apple..