???

If you are an honest person, you are not going to steal a bike even if unlocked, because you'd still be stealing it. So how is an honest person deterred by a lock? Is "mostly honest" referring to a person who will only steal an unlocked bike, and is simply too lazy to cut a lock or forgets to bring the right tools to cut the lock? I'd call such a person an opportunistic thief, but not "mostly honest."