Sorry, I hope I never come cross an automotive product designed by you.

Bert,

I think you may be a bit too harsh in this case; however if Mahmood were designing brake electronics I would consider your post too mild.

The question is "what happens if the diff lock erroneously does (not) lock?"

I do not think anything would happen of a disastrous nature, and thus a failure rate of one in 50.000 per year should be acceptable.

I can't raise my cost up because I might risk losing the contract
Mahmood,
Please do not build and sell a piece of defecation just because you can not meet a price goal otherwise, in such a case it is better to walk away.

Erik