If you want to deal with the crash and justify why the system went down because you were more correct than the other guys, then sure.

I think it's more like, 'if you want to deal with the crash in test instead of having to justify why it crashed in prod.'

Especially when that is the case, you want to be as charitable as possible when accepting input, because getting any issues resolved may very well require getting the two organizations to agree.

I don't think we've been fans of "be rigorous in what you emit and permissive in what you accept" since IE6 showed us the error of our ways. "Be rigorous in your implementation of a permissive spec" is as far as we should go.