A lot of those were 'merkins, in most states a bicycle is road legal if it has either a hand-operated or coaster brake on the rear wheel, no front brake required.
(OT: I was told that's the reason that Sturmey introduced the NIG hubs; apparently the old coaster brake hubs could lose braking if they slipped into neutral though maladjustment, and one US maker specced a load of their cruisers with them as the only brake...)
No idea, I just remember seeing a load like this
