[jaapz]

And using DNS to prove that a domain is actually owned by this organization

[HelloNurse]

Email domains of employee addresses aren't necessarily owned by the company. For example:

  - a startup with legacy personal email addresses from one or two universities
  - a spin-off sharing the email domain (and the whole IT infrastructure) of the parent company
  - cheapskates using six approved free email services

For security purposes, on the other hand, the important part is proving that the LinkedIn account is owned by the organization.

[bigbuppo]

Then there are old school ISPs where there was no separation between company and customer email addresses.

[jaapz]

So? Then you can't do this. For companies that do want more control over their linkedin organizations, it is still a useful feature. For companies using free e-mail services... they probably don't care anyway.