Different treatment of \repeat volta in midi

[pkarl]

It would be so nifty if the following snippet produced equivalent output 
in the midi file to what is produced in the pdf:

\version "2.19.38"

musicA = \relative {
    \set Staff.instrumentName = "A"
    \repeat volta 2 {
        c''4 d e f
    }
    f d e c
    \bar "|."
}

musicB = \relative {
    \set Staff.instrumentName = "B"
    c''4 d e f
    f d e c
}
\score { <<
    \new Staff \musicA
    \new Staff \musicB
  >>
  \layout {}
}

\score {
    \unfoldRepeats
    <<
    \new Staff \musicA
    \new Staff \musicB
  >>
  \layout {}
  \midi { }
}

This would greatly simplify the production of pieces with many parallel 
staves.

Should this work?  Is it documented that it doesn't work?  Why does it 
work in the pdf output? Is this a bug of \unfoldRepeats?  There are 
several warnings about the use of \unfoldRepeats in the Notation Manual, 
but none of them seem to apply to my snippet.

Output from the above snippet:

Screen Shot 2016-07-16 at 9.21.44 AM.png
Description: PNG image