Caravans with blacked-out windows

Flutel

I recently pitched my caravan next to a van that had those blacked-out windows that you cannot see into. I eventually became aware that I felt uncomfortable about this. I felt that I could have been watched in my van, or pottering about outside it, without
me knowing. 

My neighbours were probably not doing this (dull) activity but even this thought did not comfort me.  What do other people think about the blacked-out windows?