I'm willing to bet that no one on that list are intelligent, and to be honest what's 4 less idiots on the planet. Plenty where that came from.OK
http://fox5sandiego.com/2015/08/13/cedar-point-guest-dies-after-being-hit-by-roller-coaster/
http://www.dailynews.com/general-news/20080903/man-struck-by-roller-coaster-at-magic-mountain
http://edition.cnn.com/2008/US/06/28/theme.park.fatality/index.html?iref=newssearch
http://www.sfgate.com/news/article/Bizarre-Coaster-Accident-Kills-Hayward-Man-at-2992233.php
But if someone was to climb over the fence(s) and enter the ride area if there was a simple "danger, ride area sign" wouldn't they be covered?