Yes of course demand increases for UDST on downturns which increases the market value of USDT and that's fine.
In fact printing tether to ensure it's market value is $1 is a fine solution. Except for the fact that the bank accounts that BACK the tether with USD are now in deficit compared ot the UDST supply. So while the crypto market value of USDT is $1 it's no longer backed 1-1.
So now, if they're legit, tether must figure out a way to get the missing dollars back into the bank account. The most efficient way to do this is to find an outside investor and trade him all the newly printed USDT for USD. In practice this would be rather difficult to do consistently in sliding markets, difficult enough that the correlation would be low as I pointed out.
You could also exchange USDT for various COINS then sell the coins for USD which then go into those reserve bank accounts. If you have a willing exchange partner with lots of cash and a need for bitcoins then this could work pretty well. Considering Bitfnex is run by the same dudes as tether, if they are legit then this is probably what they are doing. But all that's just IF they are legit and there's plenty of things wrong with USDT outside of whether it's backed 1-1 with USD.
TLDR: Trading volume and market value of USDT does not relieve tether of actually having USD on hand for each Tether that exists.
In fact printing tether to ensure it's market value is $1 is a fine solution. Except for the fact that the bank accounts that BACK the tether with USD are now in deficit compared ot the UDST supply. So while the crypto market value of USDT is $1 it's no longer backed 1-1.
So now, if they're legit, tether must figure out a way to get the missing dollars back into the bank account. The most efficient way to do this is to find an outside investor and trade him all the newly printed USDT for USD. In practice this would be rather difficult to do consistently in sliding markets, difficult enough that the correlation would be low as I pointed out.
You could also exchange USDT for various COINS then sell the coins for USD which then go into those reserve bank accounts. If you have a willing exchange partner with lots of cash and a need for bitcoins then this could work pretty well. Considering Bitfnex is run by the same dudes as tether, if they are legit then this is probably what they are doing. But all that's just IF they are legit and there's plenty of things wrong with USDT outside of whether it's backed 1-1 with USD.
TLDR: Trading volume and market value of USDT does not relieve tether of actually having USD on hand for each Tether that exists.