Since Volkswagen AG executives admitted the deception when the evidence was presented to them by the EPA, is there an ethical argument to excuse the behavior or mitigate the consequences?

Business law -ethical 

Please follow the instruction Was it in fact unethical to program the vehicles to emit less NOx pollution during tests, if such “adjustments” were legally permissible? Why? • Could Volkswagen AG have avoided this issue by disclosing the defeat device software to regulators? If so, what were the ethical arguments, if any, in favor of not disclosing the defeat device software?

• Since Volkswagen AG executives admitted the deception when the evidence was presented to them by the EPA, is there an ethical argument to excuse the behavior or mitigate the consequences?