They were being used in 1971 in DC, as someone was hit they would move to the interior of the group, since the cops weren’t getting resistance they would back off for a while and try it again and then when there was still no resistance they just started politely arresting everyone.
What would work better than a Billy club would be a painful switch type stick, sturdy, flexible and thick enough to deliver a blow if used on the head and thin enough to use against the legs, arms and bare skin for pain.
They do have a long history don’t they!
Also they were used to break illegal strikes (going back further now)