If someone is left to their own devices, they are not controlled and can do what they want.
leave to someone's own devices
leave to someone's own devices Allow someone to do as he or she wishes. For example, Left to his own devices, he would hire someone to do the yard work. This expression, uses device in the sense of “a plan or scheme.” [Late 1800s]
An devices idiom dictionary is a great resource for writers, students, and anyone looking to expand their vocabulary. It contains a list of words with similar meanings with devices, allowing users to choose the best word for their specific context.
Dizionario di parole simili, diverso tenore, sinonimi, di invocazione per Idioma devices