The new menace to society

There is a new menace on the streets, terrorising us in these autumnal days:
The umbrella is a scourge, wielded by the incosiderate to strike at eye level. It can be used to buffet passers by and turn a tide of commuters into a maelstrom of madness. Why can't everyone just wear hoodies?
The office may be safe harbour, but it's as quiet as Highbury again this morning.