I doubt it could be retroactive, and what I do with my personal property is not the government's business as long as I am not taking from somebody else. I don't see how using third-party software to access features made available by third-parties could ever be illegal, but then ... I'll leave it at that.
I doubt it will become illegal... the only thing that apple could get jailbreakers on is breaking their eula.. their terms and conditions, when we take the device and use it we agree not to modify it in the "Eula" but that wont stop any one especially when the law on jailbreaking will stay legal.