In principle, the OP’s idea seems a good one. Many years ago, I fitted such a system to my brand-new Austin Montego; it consisted simply of routing one of the low-voltage cables to the coil via a switch under the dashboard. Unless the switch was made, the engine couldn’t be started. Actually, it probably wasn’t worth the effort because, after 7 years, the car had completely rotted away, leaving just the switch on my drive! I would assume that a similar switch could be used on a Lexus but perhaps it would cause the car’s computerised self-diagnosis system to complain. OK, OK, I suppose that this wouldn’t prevent a hybrid being driven away but how far/fast would the getaway be using just the electric motor?