My new abandoned bicycle had a lock and cable through the front wheel, so I borrowed a set of 18" bolt cutters to cut the lock. I was shocked at just how easy it was to cut the lock. I was imagining having to wrestle the lock a bit... But no, I snipped it in about 1 second, just like cutting through butter.
If I were a bike thief with a pair of bolt cutters, I could cut through a lock and be on the bike and away before anybody ever noticed. Something to think about for anybody using or choosing a lock.