You bring up good pionts. As usual, I find your broad base of knowledge/experience, very informative. Thank you.
Yes, I do keep batteries in many of the flashlights around the house and they are used very infrequently. I try to keep them "at the ready" and as such, do keep them filled with batteries.
I too have never found a loose battery that has leaked, so there is a tie in. I have a few flashlights in the car and have not seen a problem there, but perhaps it is just an accident waiting to happen. If I recall correctly, most of the corroded batteries were Eveready. Perhaps some Duracell. I imagine that even with the lights turned off (pushbutton) there is some leakage. That, coupled with minimum usage, could be the recipe for disaster.
As a side note, the G2Z I ordered after reading the notes arrived today with all the accessories as well. What a light! But, at about $90, I will be paranoid about losing it. I find the cases to carry the extra bulb assemblies to be a bit bulky, but I assume they will serve their purpose very well. The light and bulb storage cases each come with a lanyard, so no reason to order a separate lanyard.
Nice choice all the way around.