It's only possible at the highest level of decentralization which is very difficult to achieve because there almost always has to be someone behind every platform. There are as of yet no exchanges that come close to true decentralization and I doubt there ever will be.
Agree here. And the question also is, if ever there will be, will it not create doubts in the part of the traders if the platform is totally free and decentralized? If some problem occur, misunderstanding or even a very slight mistake happens, it will be like groping into the dark and one must be ready to say goodbye to his good.