to my knowladge with backplates, if the two where to ever touch, it should not short the board. but still ask for a second opinion. Come xmas. i am taking my pc right down to the bone, and adding a rad and stuff to it. when i do i am going to take off the backplate to my Maximus Extreme-Z IV and check its ground, i would think the IV to the V wouldnt change that much in the sense of backplates, and what not. so when i confirm my answer, you should have yours confirmed.
Also in EK's defense, some loops are in parallel loops not series. Therefore by having the smaller jet plate in the block, when more water is restricted, more of a volume in water can go to the other components in the system. Where in a series loop you want as much water as fast as possible threw each block, thus the bigger jet plate use.
for the 2011 socket in parallel with GPUs and chip sets, ect. more heat off the cpu thus needing more water to keep an overall lower temperature.
where smaller cpu doesn't need as much heat dissipation in ratio to GPU or chip sets therefore you can restrict more water.
Parallel Discription (EXAMPLE)
|Rad -> Res -> Pump| --+----------+--------------- +
| | CPU GPU Ram
|Pump <- Res <- Rad| --+----------+--------------- +
Well there is my epic fail at a text pic. but kinda shows a Parallel Loop.