Use of hot or neutral for light shutoff

[kwired]

If you unscrewed the bulb(s), it made the switch touch safe for repair or troubleshooting without having to pull the fuse for the whole circuit. (There were not a lot of circuits in one house back in those days, so pulling the fuse could hit all of the lights.) My SWAG anyway.

I can see some logic to that, but chances are the lamp/lampholder needs servicing more often than the switch, and you have a continuous "hot" conductor at the light. They also usually had fuses in both grounded and ungrounded conductors in the days when K&T was common.

Another problem was any ground fault in the switched lead meant the light never shuts off - maybe they wanted it to fail in this mode for some reason.