That was how Daniel Carlock was found, abandoned floating in the Ocean 12 miles off Long Beach, by a 15-year old Boy Scout looking through binoculars, returning from a trip in 2004. The LA Times has the article here:
Daniel Carlock was awarded $1.68 million after his dive boat the Sundiver failed to make sure he was on board and left him there for hours.
Now I’ve never been on the Sundiver (nor do I want to be) but every time I’ve been on a boat dive, they’ve been meticulous about making sure everyone is checked in before moving on to the next dive site. Now every boat will be on their toes and make sure they have a visual verification of the person on the boat and some type of redundancy check. Good times.