I still have the [now much scarred] "cable lock" I bought with the bike in 1972. Mine has had attempts on it so many times that I've lost count. One even tried to saw through the cable (the plastic sheath bears the scars) with a hacksaw: it left pieces of the saw teeth in the plastic as the cable itself is hardened. I usually lock it TO something with this cable if I am in a strange place, or THROUGH the bike on the centerstand so the lock is plainly visible.
I still smile to myself and shake my head over one attempt, though: the [would-be] thief hotwired the bike (and broke off my bottom side cover's lower tab, bastard) with a clip lead and started to ride off. It wrapped the cable around the rear wheel, locking it against the (then bent) chainguard and dumping the guy on his ass, according to bystanders who wondered what was going on. The bike then fell on his left leg as it fell over. He dragged himself out, stood the bike back up, set it on the sidestand, and limped away, so they said. It took me about 15 minutes to un-bend the 3/4" diameter steel cable from the (still-bent) rear spokes and straighten up the chainguard enough so I could ride it home. It was convenient that the hotwire fell off, or else I would have been faced with a dead battery after work! This was when I worked in downtown Denver, circa 1975.