[Avodah] Why does it matter who blows the shofar?

[Zev Sero]

The mitzvah is to hear, rather than to blow.  Lishmoa` kol shofar, not
liskoa` bashofar.  This is why one is yotzei with a stolen shofar; blowing
it is an avera but listening to the sound is not, and the mitzvah is the
listening.  Since this is so, why is it that one can't be yotzei if the
blower is not obligated in the mitzvah?  Why can the tokea` not be a woman,
a katan, or even a nochri, or even a mechanical system that pumps air through
a kosher shofar?


-- 
Zev Sero               A citizen may not be required to offer a 'good and
zev at sero.name          substantial reason' why he should be permitted to
                        exercise his rights. The right's existence is all
                        the reason he needs.
                            - Judge Benson E. Legg, Woollard v. Sheridan