The extent of it is
First for cricket to register the PIN with RIM the original carrier wold need to release it from their side, then cricket would need register it on their side. It can be done but cricket is not going to go to the expense or take the time and resources to do it. Not when they are trying to sale their Blackberries. It's a profit factor, not a customer satisfaction factor. Also on a side note: cricket will only guarantee talk and text on a flashed phone.