As well marked as the reef is between the Anegada Reef Hotel (that should be a hint) and Neptune's treasure, people are always running their dingy aground on it.
<img src="http://www.traveltalkonline.com/forums/images/graemlins/titanic.gif" alt="" /> <img src="http://www.traveltalkonline.com/forums/images/graemlins/drown.gif" alt="" />
Yelling at them from your boat is fruitless because of the sound of their outboard.