I carry both a tube and patches, I'll replace the tube on the road and patch and reinstall the tube after the ride unless the tube is in really bad shape, I did learn that its also a good idea to carry something to patch the tire also on my last flat the tire had a rip in it from a large piece of glass, I did have to replace the tire which was new.
But if I were a MB'r I'd carry a patch kit, tube and a few tire membrane patches like the Park Tool TB-2 just incase.
I did use a tube patch on the tire it did the job till I got back but was starting to bulge by the time I got back.