OP
To my knowledge I've never had a "foreign transaction fee" with any of my credit cards. Who does this?
The only thing I know of that you have to have cash for is the Marine Park fee.
Perhaps you've got a "No Foreign Transaction Fee" Card... I know this bit me in the but a few years ago when charging lodging at a rather pricey hotel in Paris... Seems to me it was between $100 and $200 Foreign Transaction Fee for the Hotel bill (Paris is a VERY pricey city).
I realize spending money in Bonaire is probably small potatoes in comparison, but after that bit me in the butt, I've never forgotten and like to avoid it all all costs.
Jim