How are they even buying all this Bitcoin? Are they unwittingly assisting in the Tether prints?
If money came out of thin air from tether's side there should be a big discrepancy between the daily increase in marketcap
And we definitely don't know the real numbers, reported tether trading volumes are total nonce, they wash traded them to the point that they report higher volumes than all the world stock/bond markets combined.
It's "backed by other assets", not backed 1:1 but "is always valued by Tether at 1 USD" and "Tether makes no representations or warranties about whether Tether Tokens that may be traded on the Site may be traded on the Site at any point in the future, if at all." all on their website.
TL;DR - Prepare to get filthy rich! In USDT terms.
[1] http://www.tr0lly.com/bitcoin/the-tether-press-and-bitcoins-...