I do know of one not-so-mundane piece of gear that will never be compatible with Class A GFCIs though...the Line Impedance Stabilization Network that's used when you want to measure how much RF hash some piece of kit spews out its power cord
Those things leak oh, 10-15mA to ground. By design and regulatory mandate.
@Mazura my day job's as a software developer -- my EE-side stuff's actually more Computer than power Electrical
so I'm basically an almost-an-EE who knows enough code to pretend to be an electrician (it's my Plan B in case Skynet rises and has to be terminated -- I don't think I'd have any trouble apprenticing as an electrician, if all else fails)
but yeah, the wall socket looks different if you're an RF signal headed that way, depending on where you are more or less