Comment by Bender

I second this for personal sites. Having run forums and chan sites without a CDN I found that not only is this true, it is 100% automated. The timing in emails to VPS/Registrars matches the times their scripts would crawl my sites and submit illicit content, screenshot it and automatically submit the screenshots to the VPS/server/registrar providers. That was incentive enough for me to take my sites private / semi-private. I would move them to .onion nodes but that's just too slow for me. I have my own theories as to what groups are running these scripts to push people to CDN's but no smoking gun.

Corporations are a little safer. They have mutually binding contracts with multiple internet service providers and dedicated circuits. They have binding contracts with DNS registrars. Having been on the receiving end of abuse@ they notify over phone and email giving plenty of time to figure out what is going on. I've never seen corporate circuits get nuked for such shenanigans.