That's why a little thing like the clammy hands can trick them so easily; the parents will not catch on to his plan. Seeing this though encouraged kids in high school to try to pull this act and made them believe that it can actually work since Ferris did get away with the whole thing. When his sister, Jeanie, saw his behavior she thought she would be able to get away with catching him in the act but gets herself into trouble and ends up in the police station.
Albert Bandura theory states, that behavior, environment, and person/cognitive factors are all important in understanding personality. Bandura would find Ferris unique considering the situations he ran into during his day off, how he adapted according to his environment, and how his behavior adapted as well. For example in the movie, Ferris has to make this plan believable as possible so with the technology that was available to him he managed to change the voicemail on his phone, so when people call to leave a message they hear his voice, and if they are calling for him he thanks them. He recorded himself answering the door so if someone drops by to check on him he has himself saying "I am fine thank you" or "I cannot come to the door right now, I am very ill". He made sure his surroundings were matching with what he was doing or behaving like. It is like he got people to play into without them even knowing. So observing how the technology worked and what it can do, Ferris used it to his advantage. Personal control of a situation was a big factor in this film as demonstrated by Ferris' need to manipulate even the most crucial situations. He was able to maintain control over his own behavior despite his changing environment. For example in the film Ferris, his best friend, and girlfriend decided to go swimming in somebody else's pool. His best friend, Cameron, pretended to drown and not wake up, as the girlfriend was in a panic Ferris was able to take over his behavior and stay as calm as possible to help out his friend.