  We assess a physically feasible explanation for the low number of discovered
(near-)grazing planetary transits through all ground and space based transit
surveys. We performed simulations to generate the synthetic distribution of
detectable planets based on their impact parameter, and found that a larger
number of (near-)grazing planets should have been detected than have been
detected. Our explanation for the insufficient number of (near-)grazing planets
is based on a simple assumption that a large number of (near-)grazing planets
transit host stars which harbor dark giant polar spot, and thus the transit
light-curve vanishes due to the occultation of grazing planet and the polar
spot. We conclude by evaluating the properties required of polar spots in order
to make disappear the grazing transit light-curve, and we conclude that their
properties are compatible with the expected properties from observations.
