Mostly, if I'm riding with other people, not in an urban area, etc., I don't carry a lock.
On the rare occasions when I do, it's a reasonably light cable lock.
Yeah, I know you could cut it with a pair of pliers or nail clippers given some time. But it'll keep someone from hopping on and riding away.
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"be careful this rando stuff is addictive and dan's the 'pusher'."