Believed to be protection against the good folk

It has never been clear to me why one would need protection: I can think of nothing better than to spend a week feasting in the company of the suspiciously good-looking people with slightly pointy ears, only to return, somewhat the worse for wear, to find that a hundred years have passed and compound interest has done its thing for my investments. It has all the advantages of being a vampire without the endless labour of luring often frankly boring upper-class victims to their inevitable doom and the expensive dentistry.

On the other hand, anyone spending time with the gentle people now is probably going to emerge into some kind of apocalyptic burnt wasteland with a few remaining humans living on a diet of, mostly, other humans, after climate change has done its work.

So, perhaps not: perhaps it is better to live out my life in a world which still has flowers, and leave the apocalypse to later generations. Also the fae are not accepting guests currently, I am reliably informed.