South Africa has been doing this all along under "Capital Gains Tax" @enazwahsdarb

During about 2005 when doing imports/exports using banks to hedge the fund you had to make note of price on the day hedging took place, then take the spot rate, wait for the day the good arrived and calc the value. Keep a running balance of profit/loss made from hedging the money and declare it.

This is not a new law and GAAP rulings made this feature for audit purposes.

A couple of years ago I had to laugh when a local proudly declared he had moved all his money into bitcoin, could leave the country without declaring. News for you I mentioned in a reply, you will have to do the calculation on date of purchase, current value and find the profit to declare in tax before leaving the country. Unless of course he was planning a quick run, not wise.

One sure thing in life is you will pay taxes, heck they even knock on your door when you dead, that is called government and law.

Nice article and thought provoking as to how blockchain, bitcoin and cryptocurrency will be handled going into the future @jrcornel