The Dinghy's Beach Bar does not add a S/C so we tip 20%. But in the past week we have noticed that a lot of places do. It's your call then on what to do, if the service and the food is good we tip on top of the S/C. I wish the gov't would step in and ban this practice. As for social media discount we haven't heard about that, but have been asked to give a good review on Trip Advisor on occasion to which I reply I only post on TTOL.