I have no idea if this is fact or fiction but considering the source (TripAdvisor), I would look further for clarification. I find a lot of questionable things posted there and think a lot of the "ratings", especially of restaurants are very misleading.

Perhaps someone on the island can check this out and give an accurate account and explanation. I will personally check it out in a few weeks if nobody else responds.

Any "fee" they might be charging would negate an additional tip in many cases.

I also wonder if this might not be an attempt to cover the Turnover Tax (TOT) that gets discussed on occasion.