I think there might be more to it....IIRC each sensor has it's own number printed on it (sensor is in the special valve stem and number is viewable when tire is off rim (inside the wheel).
Have a look at this site....it might have been where I read it?
http://www.toyotatpms.com/
I think each car is programmed with 5 numbers from 5 sensors, otherwise you might pick up a low tire signal from the guy parked next to you with another runner. The numbers would have to be re-programmed by dealer for each riim switch. (aka summer to winter to summer rims) Do some googling to verify, as I might be wrong on this though.
I bought a cheap set of 01 tundra rims w/o tpms sensors and plan to just ignore the light durring the 3 months of winter rim/tire use. If I have to pay the dealership to reprog the sensors twice each year then I might as well just pay someone to swap the tires instead. NOW if you summer rims are in excellent shape and want to keep the that way, this is N/A to your situation.
tk