[SI-LIST] Sacrificial ground: Is it useful?

Hi gurus,
We've traditionally used a "sacrificial ground" (a 
trace around the edge of PCBs) which is connected to 
chassis ground (when the board is installed). We also 
distribute some caps (like 0.1uF) from this trace to 
signal ground around the edge of the PCB.
1. Is this trace used to help protect the active 
circuitry when one picks up the board by the edges 
(i.e. when ESD handling procedures are not being 
followed) OR is it beneficial for some other purpose?
If beneficial:
2. Are the caps beneficial or counter-productive?
3. Should it be placed on all layers?
4. How wide should it be?
5. How near the edge it should be?
6. How much spacing should there be from it to active 
traces? To power/ground planes?
Thanks,
John
PS, I didn't see anything about it in the archives.

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