leave to one's own devices

leave sb to one's own devices (to leave someone alone to do as they wish, and not tell them what to do) — предоставить самому себе; оставить без контроля, наздора, пр.; не заниматься кем-л./чем-л.
≈ дать волю (контекст.)
≈ пускать на самотек (контекст.)

Example 1: If students are left to their own devices (=left alone and allowed to do whatever they wanted) for long periods, they will end up talking, joking, and playing around instead of studying.

Example 2: Left to their own devices teenagers are often more responsible, cooperative and sensible than we give them credit for.

Example 3: In many parts of Britain, children fail to learn parenting skills from their own parents - whether single or part of a couple - because they are left largely to their own devices as they grow up.

Example 4: In days gone by children and young people were often left to their own devices when it came to relationships with their peers. It was frowned upon to ‘tell tales’ and bullying was considered to be ‘character building.’

Example 5: Many teens are left to their own devices in Internet chat rooms, and when they talk about their understanding of media products, it is most likely with peers, not adults.

Example 6: According to prevailing wisdom, a boy must be raised with a man in the house; otherwise, he's bound to be a failure. That same wisdom tells us that mothers left to their own devices will smother their sons and turn them into sissies, and that sons of unmarried mothers are destined to a life of crime.

Related vocabulary:
[предоставить самому себе]
[throw in at the deep end]
abandon sb to fend for oneself
[на произвол судьбы]