I've been remodeling my 1924 house, and have been slowly re-wiring, and splitting up an old "mega circuit" where half the house is all wired into one circuit. In the process of doing so I discovered many hidden boxes buried in the basement ceiling. Judging by the type of wiring (cloth wire in bx) I'm guessing this dates to sometime from the 30s to the 50s.
I know this isn't right, and my goal is to remove all this old wiring, and de-energize this mess. The wiring connections inside these hidden boxes seem fine and not loose, though the wiring scheme itself seems to have been done by a madman channeling Rube Goldberg (which is much of the reason I'm re-doing it).
I'm curious about the larger picture here. What are the inherent dangers of a hidden box if the wiring connections are solid, but just foolishly covered up? It makes maintenance impossible without destroying things, but is that the extent of the problem? (And yes, I'm thinking about what old circuits I want to put AFCI breakers on)