AHHHHH that's true! We must have went to the same place because the FIRST question they had when we asked to go diving was "who's paying?". I spend a lot of time in Grenada and I know all the shops. I know exactly where you were
It depends where you go. The first time I produced my SSI ow card in Riveria Maya the shop operator said "SSI? What is that? Are you a diver? The next time I also had a PADI aow card and was ok. This year I was in Poland and the dive shop said "SSI, PADI no. If you want to dive here you must have CMAS."
I wonder how to get a CMAS card in BC.