Little children should not go to the restroom alone. However, at age 15 , you should know better to not to run off with someone at a restroom. If you have a teenager with behavior issues, it will be tough to monitor them at all times.
This girl may have had history of being a runaway, maybe drug issues, and thats why the police did not intervene.
Why do you think she just pranced off with them and did not have a weapon jammed in her ribs? 🤦
No, someone needs to go with others, especially young women, into their 20s. Fifteen is still too young to go alone.