EzekielRaiden
Follower of the Way
Sure, that's an example. Another, which I've referenced many a time before, is dying to "random orc #7" getting an (un)lucky crit at exactly the wrong time when the party can't do a blessed thing about it. E.g. no access to revivify (level <5, healer is a Bard or Druid that doesn't learn it), or the body isn't available so no resurrection spell short of true resurrection or the like, or the resources are non-existent and cannot be acquired by the party within a reasonable period of time (e.g. they're dead broke in the middle of nowhere, or in a place where diamonds and/or diamond dust is simply not available for purchase).What sort of stupid out of the blue crap? Do you mean old school untelegraphed instakill traps and stuff like that? Because I'm not a fan of that sort of a thing either.
If the PC can in fact be revived by the party and they're just reluctant to spend the resources? That's not irrevocable. The players are making a decision not to revoke it. If the PCs have an ally they can reach in a reasonable amount of time (as stated, no more than two full sessions), then that's perfectly acceptable, and one of the reasons why I try to make sure PCs do have allies they could call upon. If one or more of the PCs were clearly warned that they were doing something extraordinarily unwise and that death could really happen if they continue on their course, and they continue on it anyway, that's not random, that's a well-earned death. If the BBEG takes the body and decides it's worth their while to restore the PC to life for some reason, that's also acceptable and creates various opportunities that I think are pretty cool.
It really, really does have to be something random, and also permanent, and also something the players genuinely can't fix within a reasonable period of time. I have my standard (2 full sessions of character being dead), others will likely have their own. Making it "a hundred sessions" or the like is, I think, pretty blatantly unreasonable regardless, but making it say five full sessions? Maybe even ten? Probably fine, even if I would not like such a delay regardless of which side of the screen I'm on.