If you take a day trip to Anguilla or St. Barts you will need to take your passport with you. Other than that, we too leave them in our safe, but I have made copies of the main page with our photos which I keep in my wallet. One time we were stopped on an alleged traffic stop on the French side and they asked for our passports. Luckily my driver's license worked, but I was told, I think since I can't speak French, that I should have my passport or a copy of the title page with me at all times when on the island. Anyone else have that experience?