You confirmed that you’re dishonest by omission in your example. The fact that a counteroffer exists shows that it’s not implied you were forthwith with the price/value. Making/receiving a counteroffer implies that there was deceit, it’s just culturally acceptable deceit. If negotiations were completely honest, there would never be a counteroffer. Some Native American tribes were known for this sort of negotiation where the bottom line is stated and then accepted or rejected. They were often offended, by the implied dishonesty, by European’s counteroffers.

Extended to this situation, hiding an identity because it affects the business decisions of the other party is no different. (And I won’t continue the discussion if you want to defend your assertion that Disney is morally wrong here for being dishonest by omission.)