Having been an instructor for very large groups and also having worked on a liveaboard, this whole situation surprised me. But I was on vacation last year on a highly recommended boat and our crew bailed on people (and took on others from another boat from a different resort at the same site) despite my warning to the crew that a couple I'd been diving with for days was not back on the boat. The sad reality is this stuff happens. In both the case discussed above and my trip, everyone eventually got home okay, but it could have turned out worse. We never incorrectly accounted for divers in my professional experience and it felt very easy to keep track of our divers. If this makes dive operators wake up and practice some of the most obvious, simple due diligence, the award is appropriate in my opinion.