A comment and a question. My S20 _always_ comes on in low after being physically locked out at the tailcap. I even measured the amount of time it took to "reset" from whichever level was current, and it was about 8 seconds. I like this, because with the quarter turn lockout, any of moonlight, low, and high are accessible, from long press, press, and double click.
Question: what voltage does the low voltage warning come in on? Alternatively, how much capacity is remaining in the light at that point?