Per the manufacturer you may need to fiddle around with adjusting the button a weee bit!
But yes, There is a simple Modification Zen can make to this
mod to make the bottom button lockable.
Zen could put a skirted lock ring (Screw) at the very bottom of the
device, just screw down the ring to lock the button in place; SIMPLE!
Or I could quote Clarkson with "HOW HARD CAN IT BE"?
But to me this bit of the design leaves me scratching my head. Everything else is so WELL Thought out and there SHOULD be a reason why Zen did it this way.