I would just buy two PS3's if that were the case. One for legal online use, and the other for offline backup gameplay. The alternative could be like the 360 mod chips that allow you to switch them off before going online to prevent you from being banned.

If it did go like the PSP with custom firmwares then it wouldn't be much of an issue. Look how quickly the custom firmwares come out after the official release of a new one. The last one appeared the same day!