I ran into a similar situation a couple of years ago at the now defunct Satara across from Pineapple Pete's. When the bill came, 15% had been added on a line that said "tax" - the bill was $70 and $10.50 had been added for a total of $80.50. I tipped the waitress an appropriate amount in cash and then gave her $70 for the bill. I told her that I had lived/traveled to SXM for more than 20 years and that she should explain to the manager that I was paying only the bill and not the tax as that was not legal in SXM. I offered to speak with the manager and told her to explain that if the manager wished to call the police for me, I would be sitting at my table finishing my wine. The young lady came back saying the manager would accept the $70 because she didn't want me to leave "unhappy." Later, several friends told me about charges there for "tax" or "breakage fees" or overcharges for food/drinks. Satara didn't last long.

I don't know what the story at Kangaroo Court was (I have had so many horrible experiences there, they've been off my list for years), but the lesson is to watch your bill and don't be afraid to question. Scams like these are run as an odds based game. If you try to screw someone 100 times, and 90 times you get away with it, it's profitable. Only by being vigilant will you be part of the 10 and not part of the 90 and only by spreading the word will the 10 increase to 90 and the nonsense will stop.