I've locked up my carbon bike for an hour or so before outside. It was 100% fine. Granted, I could see it from the window of the cafe, but any potential thieves didn't know that. No one even so much as gave it a second look. If the OP can bring it inside at home and work, I can't imagine he would have any problems with it for a quick errand.
Now, this bike I could probably leave unlocked with a $5 bill attached to it and no one would touch it


Not every one doesn't trust a good lock or two, as thieves will go for the easiest target, not necessarily the nicest bike