Ive trained one or two fighters who switcthed, but for a reason. one had his arm broken 4 times by the screws in prison and had only 75% extension on the arm. But all his good work was left foot forward. Dnne properly its a great way for stopping the other guy working and to have a rest. But against a top fighter, there can be dangers as weve all seen. you make your choice and take your chance. It would take to long to go into the whys and wherefores, just to say the main problem are the eyes and reading of distance.