I've started getting very firm with them. I respond to each email with "no thank you, also stop contacting me, also here's the last person I asked to stop contacting me, but who didn't." We'll see how long it works, if at all, but after 3 separate Amazon recruiters contacted me last month I was fed up.
I replied to a first follow up (~'I don't think I'm a good fit', nevermind anything else) this morning as it happens. Almost always ignore; took one as far as interview a few years ago, which I never heard back from (no result/feedback) until a week or so ago! But I might make that a policy, if they 'just check in' after the first email then may as well try to head it off there I suppose.