Are auto pin stripes legal as a putter sight line? If not, best legal way to add one?
On page 41 in the USGA rules of golf it shows an alignment feature that extends above the topline. It is conforming if the depth is less than 0.25″ (Fig. 32 on page 41). Based on this, I would think using pin stripes to create an alignment mark would be OK. That’s my opinion and based on my interpretation of the rule.