We feel more comfortable taking the excursion perk on some cruises, particularly if it is a long day. If O doesn't get us back to the ship, that's on them. If you are on a private excursion you are out of luck if you miss the sail time. Also, I think it depends on where you are going; e.g., on a cruise from Tokyo to Singapore (since canceled), we chose the O excursion to Hiroshima because it was quite a distance from port. I think you need to trust your instincts!