Can anyone explain to me WHY this is the case? It's not WATTS that fries things, its AMPS driven by VOLTS. Are the Apple PSUs rated in watts because they do not have proper voltage regulation? That would seem to be incredibly poor design, if so.
It would cost very little to add overvoltage protection. Any DIY bench-top PSU will have it - eg ones that I use with interchangeable tips for the miscellany of PB/IB power sockets.
Rick