I'm surprised because Pit Vipers in the U.S.(which include the Rattlesnake, Copperhead & Water Mocassin) are easy to recognize by the head that is larger than the neck. (Note the head & neck on the harmless Gopher Snake I'm holding; they are the same diameter). The lady is fortunate that the Rattlesnake was a baby - smaller venom glands - & also that Timber Rattlesnakes have less toxic venom than other species.
I had heard the opposite...that the adult snakes will strike to get you to back off but will not dump all their venom, because you are not a prey animal. The younger ones have yet to master control over their venom glads so will dump 100%. But I have no idea how that might be measured. And I agree regarding the ID. Funny how someone who is comfortable handling snakes made such a goof.
I've heard about the baby snakes dumping all their venom, too & I keep reading that's a big myth. I think it's a myth because I understand how the venom delivery system works. There is a compressor muscle surrounding each venom gland & when a venomous snake bites down, that muscle automatically squeezes the gland, forcing the venom through a duct & through the hollow fang, out the hole at the end & into the wound. I don't think a snake can control the amount of venom; the gland just empties. The amount of venom delivered depends on the size of the snake & whether or not the snake ate recently, which means it used its venom on its prey.
As for snakes being calm when handled gently, this guy raises venomous snakes (to make antivenom) & he handles them without any safety equipment. I'd never handle a venomous snake, BTY: