There was this one time at band camp... oh wait... wrong thread.
I have had minor issues over the past 50-60,000 km and very few of these issues included flats... and they were all things I could address on the spot and keep rolling save for one incident where the lock washer on my Sturmey Archer AG's non drive side (these have two of them) sheared and caused the wheel to lock up.
Ended up walking a few miles back the shop and had to fabricate a new lock washer as there were no spares at hand... and had no-one to call anyways.