Listen to BryaninPHX for anything Cable related.
Nice to see you posting around these parts. 
". Some customers reported getting as many as three or four in a row to try and resolve reception difficulties. "
Ummm...that may be something else too. Technicians are engineers, who like to find the "solution of least resistance". I imagine alot of boxes get swapped out for reasons that have nothing to do with the box. You see this happening with modems too. Sometimes its just to rule certian things out, other times its at customer request, but I think a unknown portion of the time, its just applying a band aid fix because you don't know, or don't want to fix, the actual problem.
Your point still has plenty of merit though. If nothing else, maybe its worth the peace of mind. Especially if you live anywhere there are frequent thunderstorms or problems with electrical conditioning, factors that play into "actual" hardware failure.