I didn't quite connect the battery being screwed down with being unable to disconnect it. That's a horse of a different color, because you should always be able to disconnect the battery...for safety! We've come full circle. They could've put a connector in an accessible spot, even if you were still prevented from removing the battery; or a fuse you could pull. Something to be able to interrupt the circuit. You're absolutely right, you shouldn't be forced to work on hot circuits.

My previous comments were from seeing it in the context of a particular class of problem, that of distributing a thing or information to a large number of people, whose relationship to you is "loosely coupled" (little power to coerce and control); while maintaining a high level of assurance that the thing or info won't fall into unauthorized hands. It's technology in a human world, and those are the toughest engineering problems.