I just took a look at this in CS6, and it looks to me like you don't actual get to snap to the paths, only the bounding boxes. For true horizontal and vertical straight lines, the bounding box wraps tight to the stroke, so you would have snap points at both stroke edges and the path itself by coincidence, but for anything else the bounding box is going to be larger than just the stroke. This gets further complicated if the angles for the ends or the paths don't match.
↧