I think there's been a level of misunderstanding here around this.
Monk's Walk runs alongside the park, from (what was) Loggers Leap, past Burger King, to the back end of Nemesis Inferno and Rumba Rapids. Despite the adjacent parts of the park being monitored by CCTV, and security doing checks, it is still a well known spot for people to attempt to sneak in to the park. The fence isn't all that high and it's not the most difficult thing to jump if you want to. Some locals have also mentioned in the past that they've had wheelie bins stolen which have ended up down Monk's Walk, likely so people can use them as a stepping stone to get over the fence.