It is usually fatal for a snake being trapped in that netting, outside factors aside. They die from the slow suffocation of the constriction, having squeezed into the netting . . . a lousy way to go. I would guess the damage of the netting cutting into the snake as it can't back out and can only struggle forward would take some time, but how fast could one find a snake and be able to rescue it with out the snake dying anyway? I'm only playing devil's advocate, because of my breif attempt using netting over the blueberries proved what a critter death trap the stuff is. There are discussions here on BYC about using the stuff actively to trap snakes, it's so effective.