Yeah, everything is pretty tight back there already. I figured one of the reasons why you omitted a clamp was because of this. The wiring loom just seems a lot more flimsy than everything else - which is actually a lot more solid than most other gear. It should be fine as long as it's stationary.
I noticed in the pics at the geek site that he MK1 had panel mount connectors. I really like the ones on my JL Audio amps - very durable.
With other devices, it's not always the plug/unplug stress, but the downward stress from cables dangling. My component video cables for instance pull down incredibly on my DVD player's connectors (which are unfortunately not panel mount).
I'm keeping my fingers crossed that I'll be able to hear audio from the empeg in my car for the first time this weekend. (Things have been going really slow putting the insides of my car back :)
Bruno