I always assumed the Port of St Maarten's cruise schedule was accurate until I found 2 mistakes for the next week we are going to be there (May 5-12).
On May 5th, the port's schedule shows the Navigator of the Seas will be there, although Royal Caribbean has it scheduled for Cozumel that day on a Western Caribbean cruise.
On May 10th, the port's schedule shows the Liberty of the Seas will be there but Royal Caribbean's schedule has it in St Maarten the next day.
I found this website which is accurate for the dates I've looked at.
www.cruisetimetables.com/cruises-to-philipsburg-st-maarten.html