Theoretically, yes but traveller groups are so diverse, can anyone exercise control? Who ‘controls’ groups of football fans or similar? This why there is legislation giving police those powers. Intractable problem in my view.You were quick enough to condone violence against Israeli football fans and even said they shouldn't be allowed to visit Europe. Good to see your more liberal side has re-established control.
The travelling community, like every other group, needs to take responsibility for their image and actions.
When the Appleby horse fair is on, shopkeepers just shut up shop. Pubs are open but all the furniture is removed!