It's a slightly silly example, but Nordic Folkracing has successfully used a similar rule for decades. It's supposed to be a cheap form of motor racing, but that's naturally difficult to enforce; the enforcement mechanism is that anyone has the right to buy any competitor's car for a fixed price. The equilibrium is that most competitors build the cheapest car possible to avoid the risk of being forced to sell their car, which is precisely as intended.

In the case of a Harberger copyright tax, there's an obvious equilibrium - anyone who seriously values their copyright has a strong incentive to err on the side of caution and pay taxes based on a high valuation, while lots of copyrights with negligible value are voluntarily abandoned due to the costs of both the tax and the administrative burden. The difficult cases in the middle would primarily affect speculators with large portfolios of copyrights of questionable value, which is an entirely desirable outcome. We could still drive socially desirable outcomes with very low taxation rates, because a very large proportion of copyrighted works have essentially zero commercial value.

Creating a streamlined registration, valuation and purchasing platform is entirely within the wit of man.

https://en.wikipedia.org/wiki/Folkrace