I’ve done some more experiments with my three-light tester. This time, I played around with what it takes to get it to show a Hot-Ground reverse. (I did not actually reverse the hot and ground wires, but was still able to create the condition that caused the three-light tester to give that indication. Thought you might enjoy seeing what I learned.
Your first paragraph has an error right off the bat. You state that, " it would require the ground bus in the panel to be energized to 120 volts and the black wire (normally hot) to be connected to ground. " But this is simply not true. The outlet tester is just that; it only reports on wiring at the outlet. One could easily hook up the hot wire to the ground connection at the outlet and the ground wire to the hot terminal without changing panel wiring.