I have a friend on the island who works with the turtle rescue groups. When I was there once in October we went along the beach and dug up turtle nests that had hatched already and counted the unhatched eggs and freed the few baby turtles who hadn't made it to the surface yet. But I have never watched the egg laying process. My understanding is that the people watching mark the nests after the momma leaves with the date and type of turtle. They then know about when the eggs will hatch. In the fall they dig up the nests and record the number of hatched eggshells and the number of unhatched eggs and submit that info to the great turtle authority in the sky. We moved from nest to nest in the order of their laying filling out the paperwork. The last nest we dug up had more than 100 baby turtles climbing up thru the sand. We helped them into plastic crates and then took them down to the water line. At that point, assuming that the next nests were not hatched yet, we stopped. If you check my older posts (from a couple years ago), I posted a video of the event. Here is a link to my facebook page where there are some photos of the event.