DNS/Cloudflare/乗取/この説明について、ここに記述してください。

当初の実装はこんな感じだったのかも。 

 1. Someone adds the domain to a Cloudflare’s account.

 2. The domain receives a pair of nameservers. 
    This pair by default is the one of the account owner, but if the pair is the same as 
    the account where the domain had been already added this pair is switched. 
    There is also a limit on the number of registrations (way lower, orders of magnitude lower,
    than the number of combinations) in total a domain may be added after which
    support need to intervene to allow an addition to take place.

 3. Cloudflare systems will check with the current registrar what nameservers have been added there.

 4. The account whose nameserver pair coincide with the registrar’s will get authoritative control of the domain.

One of domain names is being hijacked https://community.cloudflare.com/t/one-of-domain-names-is-being-hijacked/76774