Yeah that's exactly it. That's how we did it anyway. I guess other providers may have their own secret sauce but I have to assume it's some variation of that. We paid for a pool of, I think, 1000 non-contiguous residential / business IPs and if any of them got blocked we just immediately rotated.

Honestly we never had much trouble with it after the initial engineering work was done. I don't think the providers really give a shit beyond best initial effort to make the rights holders happy.