Funny anecdote, but does "hot swap" necessarily mean "yank out without warning"? My understanding is that you might need to tell the kernel that you are going to yank out a component before doing so. Similarly after adding in a component you might have to poke the kernel and say "hey, new stuff here" before you can use it.
Still, I suspect it was probably designed to handle unexpected 1-bit errors and, like you're saying, allow for replacing RAM modules with the cooperation of the OS.
