What exactly does the power on/off button on a Dolphin 13s pack do? I know it shuts down any output and I assume it does this thru the BMS,

Specifically, I plan to have 2 Dolphin packs (same voltage) wired such that they can be in parallel on one of my bikes. In the following scenario:
- I have one of them (the secondary one) unplugged and then "use up" the primary while riding.
- I then power off (but leave physically connected) the primary and plug in and power on the secondary - both physically still in parallel
- In this scenario, is there any danger to the powered off primary pack, by say a rapid discharge into it from the secondary?
- Or does the fact it is "powered off" prevent the discharge ports on it from seeing anything?