Worst case scenario happened to us on Friday. Our family of 5 travelled from AZ to CA last week to go on Navigator out of LA. 2 vaxxed adults, 2 vaxxed kids and 1 unvaxxed 3 year old. We all tested negative 2 days before sailing including 3 year old who tested negative 2x including PCR the night before sailing. Upon check-in and another test for him at the port....he tested positive. At the time, we thought there was a good chance of false positive since he tested negative the night before....however RC would not retest. After explanation that they won't retest because how would they know which test would be accurate....it makes sense. A real unfortunate gut punch for the kids as it was a surprise that morning. Luggage was already on board and had to be pulled. That said, the protocols worked as we did an at-home test that evening which was positive and gave us piece of mind that everything happens for a reason. New Year's Eve driving home for 7 hours wasn't what we had in mind but what can you do. All part of the risk of cruising at this point...even if you do everything "right". Be prepared for everything.