IANAL, but given that the disabling of the security system was an act of commission, not omission, it could be argued that this was more than just "negligent".

IANAL, but given that the disabling of the security system was an act of commission, not omission, it could be argued that this was more than just "negligent". On the other hand, car manufacturers have no legal duty to include collision avoidance systems, so disabling one is probably not illegal in itself.