I made this video April 1, 2017 where I made this prediction:
About a couple months ago, the Puerto Rican government did exactly that through Act 40-2020 which was signed into law on April 17, 2020. They increased the annual filing fee from $300 to $5,000 that is grandfathered into all decrees.
The bill was introduced on February 27, 2020. So in essentially a month and a half, the integrity of the tax decrees were essentially shattered.
Now we have to sue the Puerto Rico Government and let the courts decide if the Puerto Rican government can do this. If the courts allow it to stand, it gives the green light for the Puerto Rican government to increase the Annual Fee indiscriminately.
I would have to plan living in Puerto Rico on a year-by-year basis, because at any 7-week point in time, I could find that the annual fees have been raised so high as to not offset the tax savings and other quality of life issues.
Even if the courts reverse the law, why would I trust the Puerto Rico government from trying to do something similarly again in the future at an angle I did not predict.