After Zero runs away the Warden decides not to notify anyone. Because Zero is a ward of the state, and has no legal guardians, she assumes no one will come looking for him if he dies out in the desert. She orders that all of Zero's files be destroyed, as if he was "never here".
When a new boy, "Twitch" replaces Zero at Camp Green Lake, Stanley realizes is he doesn't go after Zero, no one will. This eventually leads to Stalney stealing Mister Sir's truck, crashing it, and having to go after Zero on foot.
The warden didnt want to tell anyone. She deleted all of zero's files as if he was not there at all.
Zero gets replaced by another guy :twitch" Stanley thought that no one would get him so he himself went and stole sir's car but he crashed the truck into a hole making him go on foot!