After serious thinking Andy Burns wrote :
Difficult to get very far from the blade when you're holding one, but they
are fitted with a "chaincatcher" never seen footage of them in operation
though ...

I had to buy one in the spring, when a tree came crashing down. It has
a 'trip bar' just in front of the main handle. If the saw flicks up in
use, your wrist hits the trip, which brakes and stops the blade almost
instantly.

A bit intimidating to use at first, but I soon got used to it.