In case the retroreflector is just a glas window, the Fresnel equations apply and for an incidence angle of $\theta = 0^\circ$ the reflectivities $R_p$ and $R_s$ for parallel and perpendicular polarized light are the same (about 4%), thus the polarisation of incoming light is preserved, correct?
From the answer in Polarization and mirrors I learned that a (perfect) mirror would preserve polarisation as well.
But what about corner reflectors? Or cat's eyes on bicycles and retroreflectors on clothes like sailor jackets, life vests, working clothes etc. (no idea how these retroreflectors work at all...)?
And how is all this in case of circular polarisation instead of linear polarisation?