Loose Crank Arm Problem

I saw a guy this morning at the side of the road who had snapped his crank arm in half...shocking start to the day. Pedal clean off under the shoe!

I've had the whole arm come loose before, so also tightened it. Been OK since. That, plus a clean up of the bracket - not alot more you can do I would guess?

Was he a courier on a blue low-pro Eddy Merckx?