[SI-LIST] EMI fixed by flooding?

Last summer there was a good thread going around about ground
floods and their effect on EMI.  I am interested in
finding out the opinions of those who care regarding the
following problem.

First some sarcasm. We all know that good design is verboten when
the band-aid box is full.  Given this I'm been given a severly failing
design, a box of band-aids, and a set of rules I'm supposed to implement.
(By severely failing I mean the product did not pass FCC part A emissions
because of large emissions at the system clock frequency.)

Back to the rules. The rule that's got me uncomfortable is I've been told to
flood
the outer layers of a backplane (the culprit) with Frame gnd.  This will fix
the EMI failure. Ok... does it?

Some background:

The box that this backplane is going in is metal on several sides but
has openings for cards in the front and cables in the back.

The box is tied to Frame (i.e. Earth).

Digital GND (just a name to imply not Frame GND) is used for signal
return on *some* layers of the backplane.  Low voltage power is used
for signal return on other layers.  Not all signals that transit the
backplane
use the same common reference.  Hmmm...

Currently the outer layers are microstrip (soldermask coated).
If I flood the outer surfaces of the backplane with FGND and I have
a dielectric thickness of around 6 mils to DGND haven't I just
introduced a great AC path to FGND that would not have existed if the
box metal was allowed to float?

And by doing so doesn't this help increase chances of emissions?  And if a
"farday cage"
is open on two ends does this concept help?
It seems to me that the cause of failure has to do more with the fact that
they
have a gazillion (power of ten higher than yotta) cables going out of this
chassis and
the return energy for the clock has found a lower impedance path across the
cables and
therefore has created a loop which is radiating.

Thanks,
Bill
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