Even if this is true[1], it never hurts to consciously limit the places where information flows out of your system. The idea is that securing one point is easier than securing n points.
[1] I don't doubt the flow of information, but the rate at which that information can be leaked through a signup page can be severely limited compared to a password recovery page.
[1] I don't doubt the flow of information, but the rate at which that information can be leaked through a signup page can be severely limited compared to a password recovery page.