I agree with John.

     It's not a bad design; it's a good one; twice good!

     Think about it!  The grounded shield allegedly helps reduce radio
     interference; it might also reduce interference to that expensive
     thing we call "the Brain".

     And finally, as the original poster found out, it acts as a fail safe
     device, namely if the cap and/or wires/wire connections deteriorate
     enough such that the electricity is able to look for other places to
     go, the grounded shield more-or-less safely conducts it away.  'Course
     performance suffers, but is that the fault of the grounded shield?

     -Blaine