I read your quote and the only parts I understood were PJIA=airport in st Maarten, G&T= gin and tonic, GC= Grand Case. The rest, as you state, was lost on me.
I think people do this to avoid too much writing. I just ask what they meant when I read someone's post. Or dismiss it because it means nothing to me.
They stated the post using the abbreviations was a "parody" so some of it may not make sense. It was an example.