Can you see through light filtering shades? This is again a question that can be answered with yes and no. Yes to shangri la light filtering shades or blinds with a gap on the side. However in the last case anyone who wants to have a peak, needs to come very very close to your window. Not meaning it is impossible though. No to blackout shades ideally with some drapery on the side or window blockers. No one can see through this window treatment, if they are closed of course.
Shangri La Light Filtering shades do not offer full privacy at night whilst the blackout or dual shade version does. However to close even the smallest gap at the side, which is necessary as the valance needs to be wider than the fabric, Keego Blinds offers window blockers that can be easily placed on your window frame next to your shangri la blinds. The other option to solve this would be a nice set of curtains on the side of your window. The curtains have the advantage of being better looking than PVC stripes, especially if you choose shangri la window shades which are a stylish option for your window treatments.
So, yes you can see through light filtering shades and there is not much you can do about it other than to choose a blackout fabric for your shangri la blinds or other window treatment options.