I don't know, maybe he was that bad at his job but in those couple hours he attempted four or so times to fix it, the patch never held the air. I just credit him for not giving up despite it getting dark and late. They also kept my bike safe until I came back next morning... Part of the problem might also have been that the tube itself was way too small for the tire (thanks, Drei Bikes in Cebu City who mounted a 120/90 tire with a 90/90 or so tube - first and last time I have been there). Carrying tubes has the added advantage that I don't have to go on a search for a vulcanizer in the first place, I can just go about fixing it where I am. Already paid off few weeks ago when I caught a big nail that left a 5cm cut in the rear tube in the middle of nowhere. And its my bike, not a rental :) rim locks are there and will go in next time I change tires.