As context from the social care side of things, my dad worked in an agency that specialized in troubled kids in care where they specifically take kids into an outdoorsy environment, staying in rural areas and doing hiking, swimming, biking etc.

The whole point of this is to unsettle them by putting them in an environment where it is much more difficult to get drugs or involved with crime. These kids exist on a spectrum from not very smart and a bit lost, to kids who know exactly how to manipulate adults and abuse the rules of the care system (not that they aren't also victims).

Obviously, for various reasons the kids would choose to leave. They could be having fun all day and then have a breakdown and attack the staff in the evening. They could decided to jump out of a moving car. They might just decide to walk away.

Due to the rules of the care system, only in situations of violence could staff use specific restraints to hold them in place. If a child just left, then you could follow them but only the police have any power to return them. And a lot of these kids were very resourceful, including a few who managed to make it hundreds of miles with no money.

Ultimately, it's a problematic situation but the idea is to try and protect children who have been in very serious situations. The social workers have very specific roles and obviously are in a position of trust including having to sleep in the same buildings etc. Having specific rules around what they can do vs. what the police can do helps to ensure trust and stop false accusations (as well as have real accusations taken more seriously).