The "re-test in 7 days" requirement is one of the things which the French used to justify opening St Barth's borders. The absence of that requirement in St Maarten was specifically stated as one of the reasons for closing the French side/Dutch side border.

As to what happens if it becomes a requirement and you don't do it, what happens now if you don't do the daily check-in every morning for the first 14 days of your stay?