Go ahead. Make the scene.
You're not at fault here.
If their kids are making trouble like this, the parents need to know. And knowing that the natural consequence of their behaviour is shaming both kids and parents is one of the best ways to motivate the kids to do something else. Otherwise it is just a game between you and the kids, which the kids will win, and the parents will be blithely unaware.
Literally an announcement like this, A group of kids is currently trying to kill themselves with the office supplies in the next room. We'd strongly appreciate it if their parents or guardians would take responsibility and remove them. Thank you.
I think that would result in significant improvement...
Cheers,
Ben
