All very interesting input.
I've only measured the hot side of an AC plug a few times in my years. This most recent time was to show someone what 60Hz from an outlet looks like for real.
I don't remember every connecting the ground on the scope probe as I just leave it dangling.
Most likely this would all make more sense if I someone was physically showing the connections and/or how one could get injured. Personally it seems like very little can go wrong providing one doesn't slip with the probe and short both hot and neutral (or hot to Earth ground).
The other way to get injured would be to unplug the scope probe and accidentally touch the end while the probe is connected to the hot.
In any case, I don't plan to measure the hot directly again, but sense this scope has a roll over or something causing the higher voltage measurements to show lower than they are.
