Icing is a huge concern. On a drone it just adds weight but it can add up.
Don't fly through clouds.
Flying near waterfalls is where you could find freezing mist. That can accumulate very fast.
Agree with Cafguy, a shinny surface probably confuses the downward sensor. Sorry I’m old fashioned, I always use a folding landing pad, 1. To provide a clear source for the downward sensor to pickup on and 2. To prevent any dirt from being blown...
Can't imagine any sort of comprehensive permanent drone ban will fly in the US (pun intended). I get what it's happening the OPs case--but even that will most likely be temporary.