I just strung a Wilson Trance OS for the first time tonight. I was intrigued to find soft rubber grommets on eight of the center cross strings. I haven't strung rackets for very long but I don't ever remember having a racket with anything but hard plastic grommets. They were a little 'sticky' when pulling the cross strings thru, but other than that, they were no problem to work with. I would guess that this would be a great way to make a stiff modern stick a little more arm friendly. I'm curious as to why these haven't been used more in the racket industry. Any thoughts?