They will be submitting fraud information like any other financial institution. We have also heard that they track where coins are sent to from their wallets and have closed accounts on that alone.
Nonetheless, if you haven't spent or sold any coins, you don't owe any taxes. If you have, you would need to calculate if you made any gains (or losses) and report them as part of 1040 Schedule D.
also if you are below $600 per year as income from bitcoin, you don't need to declare anything
This is wrong. All gains need to be declared.