There's no ethical reason required to tell the electrician what you plan to use the 14-50 outlet for.
1. I was responding to the suggestion that an EV owner lie about the application in order to get a better price.
2. When you teach children rights and wrongs, there's little difference between lying and not telling the truth.
3. If we're talking ethics, it's poor form to only think of yourself and not those who come behind you. Be honest, find an honest tradesman, pay a fair price, spread the word. Everyone wins, not just you.