I have never really had any luck hunting right on rub lines. However, I have had luck using rub lines to get an overall idea as to the pattern of a buck. For example, if you notice the rub line generally going from a secure bedding area through a funnel towards a feeding area then it is a safe bet that a buck is using that overall area but not necessarily the same trail.

I haven't noticed any rubs yet but I am going out Friday night to do some checking.