Oddbean new post about login | logout It isn't difficult to enforce with a public blockchain and businesses who don't want to run afoul of the law.
In the future, layer 1 bitcoin transactions will likely not be used for salaries. So payments will not be public. Perhaps governments will ask companies to report all salaries. Like they do today. However, in a world when the government can’t print money, it is an interesting question as to the cost of that enforcement. It may be too high. But you raise a fair point.