I also wonder about the opposite situation: someone turning the whole volume up because the bass doesn't sound loud enough, raising the other parts with it. Having the bass adjustable could help there. Some songs already have plenty of bass, so it makes sense to turn it down for those, and perhaps have a dynamic limiter when it gets excessive.
By "blocked" I meant the impression of music sounding too close to my ears, rather than my hearing feeling blocked after listening. Of course, feeling softer doesn't completely establish that it's safe either.