I don't bring a bike lock on distance rides, but I'm also the sort of person who rides their $3,000 custom brevet bike as a year-round commuter and leaves it locked up outside of bars and pubs in the middle of the city. I have had bikes stolen before, but it's usually because of stupid stuff like leaving it locked up at the same street corner, day-in and day-out for six months.
most people are not potential bike thieves, and most bike thieves don't stake out rural convenience stores waiting for careless distance riders to let their guard down.
but, with that said, one should do what is important to maintain their peace of mind and enjoyment of the ride.