Of course I agree, all splices must be accessible.
But, has anyone else ever encountered a factory splice in a roll of wire? Once I did. I noticed a very small bulge in the insulation. When examineing it closely I found that the area was much stiffer than the other areas of the wire. So, I peeled off the insulation to find a neat resistance weld. They had overlapped the wires about 1/2" and welded them together!