Just in case you get in that situation, it's always good to have some first aid or sports tape.  Just wrap the toes or put an X on whatever spot is starting to rub and you'll be golden.  I did hike about 2-3 miles on a jeep road last spring in my tele boots but I taped even after the blister started and the walk back was fine.  The next day we hooked up with some 4WD buddies!!!