Long ago the IRS requested to Coinbase to send available information about US citizens, for tax purposes and other stuff. Coinbase was able to refuse but seeing how big it becomes with the time passing, perhaps in the near future, it won't be able to refuse and will have to obey.

You have to think about it, if a country is able to do this, other countries will be able to do the same. And if you're not reporting you gains/losses to your taxes department, you know maybe in the future you can be in trouble.

It's like if, during a tax audit, they ask you to give them the receipt for your purchases. What will you give? A screenshot of an account in which you used bogus name?