I too have flown many uneventful carib flights... though i will share the following: if you are alert you will hear the FA ask where so n so is seated at beginning of flight... they are pleasent and ask a few non discript questions. Everything goes as planned.
Then, at arrival they give random special instructions before deplaning. Please remain seated we have (pick anything vague reason) onboard.
Note: none of this is random...once on the gateway, look to your left. There you will see several unassuming officers hiding behind airport staff. Said mr or mrs so n so will be escorted off the plane discretely (passengers deplane after officers in position). Passengers are never the wiser.
I have even followed rcmp seperating a senior husband and wife (male vs female rcmp officers) at the yyz airport fron sxm flight.. quite the escorted walk of shame... if you notice. I wish i could watch it on Border Patrol...
Sooo, yes it happens for various reasons, though never such extreme activities have i experienced to carib as that ruckus.
But, i have witnessed air marshalls on Vancouver tarmac ( to T.O. flight).. phew that went down fast.