some people hack so some times aren't 100% true hehe. But literally just practice a lottttt at the parkour you want to get a good time at and yes. that's basically it c:
Here is the actual reason why- and it's not always hackers. When they make new parkour maps, they sometimes forget to disable /fly. People flew to the end and got fast times. They never got around to resetting them, and if they do- yes it can be hackers also.