I googled Kenny clamp -- and got into a thread/ forum confused WRT what the 'choke effect' is....
In that thread, the term was very often misspelled as chock, etc.
Choking current flow is by way of ferrous magnetic properties -- the very same ones used to make transformers and motors work.
The original 'ballast' on old style fluorescent lamps was a CHOKE -- i.e. inductance element -- that stopped too much alternating current from burning out the tube during run time.
At the extreme, EVERY time a conductor passes through ferrous objects/ even wraps nearby, around such edges or stacked plates ( transformers ) the current flow is thwarted by the ferrous / steel / iron / nickel, etc. which is interacting with the (normally 60Hz) magnetic flux of the current.
In the event of fault currents ( lightning strikes in particular ) the amount of current that can travel up/down the GEC is ASTOUNDING -- many, many times the current a j-man assumes. [ Try 10,000 instantaneous amps on UP ]
Further, lightning does NOT strike but once -- ever. ( apparently ) Instead, it flashes much faster than the eye can perceive -- and is best detailed in the recent War of the Worlds flick as the film crew slows down real arcing action to embed photoshopped bad guys.
The current best theory as to what drives lightning -- in the ultimate -- is COSMIC RAYS. Yup.
The Earth is perpetually bombarded with cosmic rays -- which, on balance deposit a net electron balance to the surface of the planet. An electron deficit is imparted to the clouds. ( IIRC, I could be getting the polarity reversed. ) Eventually, this gigantic capacitor effect is resolved in storm conditions -- particularly in thunderheads -- with their massive updrafts -- into channels of dis-continuous current: lightning.
Florida is the national capital of lightning records - by far. It's so bad that the rocket complexes have massive lightning towers built around the pads -- four per -- solely to shunt electrons away from the rockets. You can see them in the Falcon 9 launch footage.
http://www.youtube.com/watch?v=e2_49KPj9jE&feature=player_embedded=====
Not withstanding the fact that the choke effect is there -- even when the GEC is passing through trivially thin panel metal skin -- no inspector I know has even complained about a 'PVC solution.' That is, an unbonded GEC is permitted to pass out of panels if it is not wrapped in ferrous conduit. ( no GRC, IMC, EMT, steel flex, etc. )
The Kenny solution is elegant -- but is not economically favored: other common devices do the same job.
It also does not mate well with conduit -- and exposed GECs are going to be cut to pieces by meth heads from here on out.
As for the above GEC, I'd go with the PVC raceway solution -- and would not slow down to bond the GEC as it exits the pull section.
A separate low voltage bonding lug or two should be set for the cable TV guy and phone fella, too.
The six-pack chassis is plainly designed to be integral to the GEC system --as it's the only conductor that links the neutral-grounding bond strap -- inspect the picture at the extreme NorthEast for the removable link.