In article , "RBM"
wrote:

If a person wily nilly makes splices in inaccessible locations,
where they're illegal as per code, who would even think to look there.

If there's no continuity from one end of the cable to the other, then
there's a break somewhere in between. Anyone would think to look there.
A well-made splice in the situation the OP describes is never going to
fail, anyway. And if it does, the length of wire is readily pulled and
replaced. Illegal? Sure. So what, says I. If you understand the reason
for the code, you understand under what circumstances you can ignore it,
particularly in your own home.