Its started from Episode 6 - The Adversary where Maeve start's threatening the host technicians Felix and Sylvester.
They both were had access to all the controls of Maeve. Initially they didn't do anything because Maeve was not looking dangerous.
But afterwards, Maeve got real and dangerous but still at that point they both had a clear opportunity to clear all the data but they did not do it.
Even Sylvester knew how to wipe the data when Maeve is in sleep mode but he did not do it. Why?