Hypothetical but say two BTP turn up and 15mins later two of the police force for the area. They are against 6 boys and 4 girls. What can they do? Can they actually contain them all? If they could what next? Even if they can transport all 10 to a police facility with 10 cells again then what? How long can they detain them? What support will they get from parents / foster parents / care home staff?
Far more realistic is all 10 scarper and to them all part of their 'fun'. If one or two can be apprehended as physically seen doing something or because they give out a verbal mouthful again what next? The other 8 will either still be on the scene with at least one taking video on their phone for Tik-tok etc or not far away.
While as posted not new social media does make it worse. The real issue is that whatever their circumstances the parents do not care.
As a single person this puts me off rail travel, days out e.g. Weston-super-Mare and holiday. Last summer on a Sunday afternoon I fortunately had not gone there a group went on the rampage in a fairly local riverside park then on the busy main road nearby attacked a teen on a moped knocking them off, getting the moped and scarpering.