> So, are we discussing ethics or legality?

No.

I'll make an analogy: Engineers hate it when sales make commitments on behalf of engineering. Can you not imagine how lawyers might dislike engineers making legal commitments?

When dealing with people outside of the org, lawyers want from engineers what engineers want from sales - be vague and don't create obligations you do not fully understand. It is still perfectly fine for a sales guy to privately point out a bug - just don't shout it to the customer.