John in New Mexico
It sounds like that hot is the power that is being switched to the light and the connection made after (?) the switch is going on to feed something else, either more lighting or some outlets. Its not the way I would have done it (I twist the two hots and a pigtail for the switch or outlet together and then nut it) but there's nothing wrong with doing that. I would take that any day over the modern crap like the stab connection outlets and switches that make contact on such a tiny area.
Out here the states usually follow the IRC rather than the NEC. Its been a long time since I worked with the code book (2005), but I don't remember much about wiring methods being in there. I was mostly trying to pass a test for a owner/builder electrical permit and memorizing the stuff for the test. Wiring methods were not on it for whatever reason.