I haven't seen this lately, but while watching some older vidoes, I see SVB and others racking the balls, then tapping the head ball with the triangle and sometimes wiping the head ball with their finger. Are they just trying to get everything frozen, or are they possibly manipulating the rack to their advantage? I know people sometimes tap the balls with another ball to supposedly just dent the cloth a little bit and help things settle, but it seems to me that it should be done while in the rack if at all. One time I heard some pros discussing rack mechanics and how huge of an advantage it is if you know how to manipulate the rack. I was glad to hear rules a while ago about not being allowed to do this anymore, but I'd like to know if this is a move if I come across it.