So if you bought a battery and never visited a Radio Shack store or website again, you would not - in fact - have made any express or implied agreement to accept the modification, and the original agreement would apply.
This sounds like something an aggressive lawyer could have some fun with.
The ability of the company to modify the agreement without your approval or knowledge is written into the agreement. It basically does nothing at all from a legal perspective.
This sounds like something an aggressive lawyer could have some fun with.