I viewed the Videos again. The concept from 300mods (Australia) and the technical implementation of the kill switch demonstrate real professionalism; this man knows what he’s doing.
However, if you forget to deactivate the switch before starting the engine, you’ll trigger a temporary error code—much like with the 41.22 relay. While the specific error-codes likely will probably differ, I imagine Toyota can spot them in the logs. It is in my opinion therefore smarter to find a solution where the alarm system —which is necessary anyway— automatically handles the switching.
A CAN-Bus alarmsystem can also be implemented using a contactless reader, meaning no wires need to be cut. However, this setup prevents the alarmsystem from electronically protecting the CAN-Bus against injection attacks. You have to build an analog immobilizer.