Is mining cave walls safe?

[VDZ]

So I read in the announcement thread that cave-ins can apparently be fatal now. (Right? Jorb never clarified what he meant by 'serious damage'.) People pointed out that this would be insane for finding nodes, but the conversation was dropped at some point and I don't think we heard any response about this from Jorb.

So is it currently the case that mining a cave wall has a random chance of causing a cave-in, as it has been in world 8, and that such a cave-in can be fatal?

[Casual]

I was searching for nodes inside of cave today and after finding one and mining for a little bit, I got indeed hit by a cave-in, but surprisingly it didn't kill me. It just dealt around 25 of HHP damage to me (and full SHP of course). Though it could be that I was quite lucky as I got hit only by a small rock and one tile on the right from me there was a 4x that big cave-in so I guess that this one would kill me

These cave-ins appeared after I have mined around 2 tiles away from cave's wall.