I use a connector loop i made to keep the switch off when the packs are in storage or being installed with the switch unplugged. You can make one by taking a servo cable and cutting one side off then shorting the center wire to one of the outer wires. Plug it in one way and the pack is on, take it out and plug it in the other way, and the pack turns off.
Also, it takes time for the switch to fail on. It doesn’t happen right away. You have a minute to get it unpluggled and plugged back in. Often they take longer than overnight to fail into the on position. I’ve never had one fail on while actually working with it, but i have had them sit for a while and be stuck on when i came back. Eventually they will fail into the on position, how long it takes seems to be randomly longer than a few hours at least in my experience.