Well, I never even thought about checking to see if our speakers and subs have fuses, which I thought they would have, but don't. All my amps have fuses, and the powered speakers and subs have amps, so, wouldn't they have fuses? I guess not.
With that said, my amps got hit with a electric utility event on a beautiful and calm night, where the power went off/on/off/on/off/on in less than two seconds. Like I said, all the amps have fuses, but they all suffered some damage, and the Krell got hit the worst - and it has the most fuses. The Krell has two fuses on each amp blade, and a bunch of fuses elsewhere, but only a couple fuses were blown - and continue to blow each time power is applied.
The point here is that fuses aren't a guarantee for less or no damage, but one would think there would be a fuse on the main power connection of a powered sub.