...And then they'll eat people!
Fetch the garlic and the silver-tipped canes!
I thought that only happened in Romania... 
Here is a little debunking, whilst on the subject of Romania, the Carpathians and up to the Tatras. We all know of the folk stories of people who feared neighbors who rarely, if ever ventured out in sunlight. This is an attribute given to the 'undead' or Vampires of fiction.
I developed an eye disorder in my late 20's which caused corneal distortions and with them, painful photo-phobia- or aversion to bright sunlight. (Since then, I have had the problem surgically corrected - an option not possible until the 1970's.) My ophthalmologist was a Jew of East European background - from the same regions as my family. I mentioned to him that there were four of us in the local parishes, Orthodox and Greek Catholic, whom I was aware of who shared this disorder. Outside of them, I never heard of it. Anyway, he mentioned that there was some research indicating a genetic issue among certain Slavic sub-groups and this eye disorder is more common there than elsewhere in Europe.
Duh - when people were superstitious, they made up reasons why those afflicted would stay indoors on bright sunny days when work was to be done in the fields.
Many superstitions can be likewise be debunked when analyzed.