[BrianG]

Yeah, that does suck. Technically though, there really is no need for that to happen. FETs generally simply do not conduct if wired backwards, but they don't blow, so those are more or less safe. The parts that blow are probably the electrolytic capacitors and the controller circuits. The caps are really easy to replace as long as they aren't surface mounted. The controller circuits could easily be protected by a simple diode, especially since those circuits aren't high current. IMO, it's simply bad engineering for the most part...