Only problem I have with those is that, technically, they may not be compliant to the GCR, which states "shall cut all electrical circuits but not an on-board fire system" (my emphasis). As I understand it, the latching circuit on those is always hot. Thus, you must ensure the latching-relay circuit is properly fused at the battery. Without that, in a crash if one of those wires is grounded it could cause sparks/fire and potentially not drop the master circuit. Can you post a circuit diagram of it?

Regardless, they're good systems if installed correctly, and I don't think anyone will give you any grief over it at all.