The owner of a pro-shop advised me that there is some risk of damaging racquets when using a stringing machine with a 2-point mounting system. He said that he wouldn't string an expensive racquet on such a machine, citing that if you have 18 main strings and you're stringing at 60+ pounds, that is over 1000 pounds of tension on the racquet. With no side supports, there is a chance of the racquet cracking. What are your opinions of 2-point mounting systems? How big is this risk?