It would still be a good idea to have backend check for this. - If javascript breaks, (or get blocked by extensions) there should be a check for contradictory

It would still be a good idea to have backend check for this. - If javascript breaks, (or get blocked by extensions) there should be a check for contradictory answers. - If on future iterations on the UI (more often than backend) logic breaks, backend help improve how to debug the UI update Just to mention a few reasons.