Motorcyclists rampage?

Just about to head over to Glasgow and heard much revving of engines and lots of smoke being pushed into the air from the burning of tyres. At the traffic lights were around 30 motorcyclists and I managed to snap some of them as they sped past when the lights changed.

Depending on what you read, they either went on a rampage around the streets of Edinburgh or alternatively rode the streets celebrating a fellow motorcyclist who had been killed over the Christmas period.