I also worked at Rock N Roller coaster.... and the heights are there for a reason.......people do dumb things when on vacation..... one woman sneaked her too short daughter on the ride (with a pony tail/hat combo), then the mother decides not to ride and goes through the chicken door...daughter gets on the ride... as the train leaves the loading area and into the launch area, daughter decides she wants off...NOW....
At the time I was there, three cm's worked the load area... one on each side of the train checking harnesses, and one in the control booth. For awhile when i was there they had an issue witht he fire marshall and had someone outside the chain link fence right as you exited the preshow (they wouldn't let them lock the emergency exit, so a cm stood there). However there was no CM there at the time...
Daughter..who is several inches too short... decides to wiggle out of the harness. At this point the train is dispatched, and the next one is being loaded. I'm in the control booth (pre cameras), and you had to basically stand up to see the launch area... I happen to glance over and see daughter 75% out of the harness, screaming... I managed to hit the estop with on the 2 of the 3-2-1 countdown... a couple of seconds later and who knows what would've happened.
Suprisingly this wasnt the first time it happened, i had seen it happen w/a cheerleader (anyone who'se been down around now knows about the groups i'm talking about) who decided she didnt want to ride and wiggled herself out.
Normally the heights stated, and probably lower, are safe. However, people are morons. They need to be protected from themselves...
As for the height sticks...it is true that there is an issue keeping them accurate...the ones at coaster were themed as giant drumsticks... and the bottoms would wear down unevenly, eventually they put a metal plate at the bottom....