I've not seen anything to indicate they are targeting heating systems, in my area. The peak shaving letters I received, while not related to smart meters, were talking about shutting off AC, not heat. I doubt they'd attempt something for heating due to the heat strips. And, heat is going to be most demanding while its the coldest out - at night. AC is most demanding during the day, when all the businesses are at their peak also. Just look at how they label the tiers in a multi-tier pricing program, day = peak, night = off peak.
Keith