I wish they had gone with At least 2 copies offsite - that was one of my first thoughts too.
Then I remember that I used to do backups at most once a year until I moved to the Mac and Time Machine.
(edit: clarify sentence)
Then I remember that I used to do backups at most once a year until I moved to the Mac and Time Machine.
(edit: clarify sentence)
And two copies is still pretty low for flaky infrastructure. They're basically setting up your data as a torrent cloud, except there are no seeds if you lose your equipment, so you're trying to download fragments from a bunch of other machines, and each fragment is only on a couple of machines.
And you're right - 2 copies would mean 1TB out of 3TB.