This is the fundamental reason for the SKREEM system. The ECU will NOT start the engine unless the SKREEM reads a valid code from the RFID chip in the key.
PERIOD.

This was mandated by the insurance industry in the EU over 20 years ago, as cars were vanishing off the streets faster than they could raise insurance rates. The industry responded and our "SKREEM" system is MB's answer. It is a very effective answer, the only way to steal a Crossfire is to tow it away.