Exactly. Programmers will just put "default: break" because of this annoyance without thinking too much if it should be this or assert(0).I think that "final switch" should have the function of checking that you covered all cases, be it with a default case or not.
A better warning/error message may help here. Please have a look at this PR:
https://github.com/D-Programming-Language/dmd/pull/3287
