I noticed earlier today that if you follow someone into a cave and they haven't moved from the entry spot, you'll be stuck on top of them and won't be able to move, not even to leave the cave. I haven't confirmed it, but I suspect the same happens with entering/leaving buildings as well, and probably also with items in doorways and cave entrances. That means you could essentially seal a cave or maybe even a mine off permanently by moving an object like a basket onto the spot where you enter the cave, as everyone entering would have to travel to hearth.
A grim thought indeed. I'll probably test if it works the same way with baskets, etc. later, but that'll take two people to be sure I don't accidentally seal the cave. I'll post again when I know more.
I would have provided a screenshot but that would require undue effort.