It’s easier to understand that rules are rules. She complained that she knew the rules but decided the cruise ship was being too rigid. It’s also easy to understand that, in your case, the ship WILL wait if it is an excursion booked thru the cruise line. And it’s easy to understand that they make it abundantly clear that if you go rogue and find your own private tour, you are gambling that the ship will leave without you. Some people like to gamble..then complain when they lose.
We went around the tip of south America on Holland America (Buenas Aires to Valparaiso). There were two long land tours but both ship operated., No problems. I have been carnival also. HA was far superior and no kids running up and down the hall at 3 AM
If you ever go to SA take time for Iguazu Falls, Spectacular with a huge Argentinian national park around them..