Here is the reality of Johnson's Reef and the heavily traveled waters around Johnson's Reef. When the sea is calm, the light conditions poor(or just right) it can be hard to notice for some helmsmen. Johnson's Reef is one situation where using a real chart and dead reckoning will keep you safe. Without a proper chart the sailor new to area can easily get confused along the shore of St. John with the thinking safe deep water is to the north away from the sand and beach. In the some light or weather conditions Johnson's Reef can be deceiving from any direction to the skipper without a chart and and poor situational awareness. Sure a chart plotter may help, a chart plotter that is zoomed in to the incorrect level can lead to disaster. My point in the right conditions you cannot miss Johnson's Reef and only an "idiot" would end up on it. In the wrong conditions a boat not using a proper chart can end up in disaster on Johnson's Reef. Here is a picture that shows dangerous Johnson's Reef and the deep water all around it. Someone in each crew should be always be tasked to maintain situational awareness with an actual chart. That person should not be the person with his or her hands driving and maintaining the lookout.
http://cdn.c.photoshelter.com/img-get/I0000CusTgpWOWbg/s/860/860/Aerial-IMG-5475.jpgWhat that does translate to. In many cases on the charter boats. The skipper should be delegating the steering to others while the most senior person on the boat provides greater focus on the navigation and safe passage. The moment there is any doubt where you are? Or "what is that mark for"? The vessel should stop until the situation is determined.
