Levels 3-4 on the graph in the below link have had studies showing that there's a 'gap of danger' (particularly at stage 4) where human's grow comfortable enough with relying on the automation to lose the ability or awareness to take over when needed. While this is far more critical in situations like automated self driving, the principle is the same. <https://www.synopsys.com/blogs/chip-design/autonomous-driving-levels.html>