Should be easy enough to test - in fact, I think someone did test it, but I can't remember the result. Set up tripod, attach camera, tape a laser pointer along lens barrel, observe laser pointer when you tap on tripod. Might be worthwhile to check how much vibration there is when you trip the shutter as well.
maybe the tripod makers can look into putting dampening materials/fluid in between the walls of the tubes or between the interface of the head and the legs to stop vibrations from travelling through.
In the audiophile world, there are many, many exotic solutions to stop unwanted vibrations from the source (CD, LP, Amp, speakers etc...) reaching to other parts of the component chain. From spikes to multilayer materials, to active and passive anti vibration devices (ie. vibrates out of phase with the source vibration, thereby canceling the vibrations)
Even in PC, the vibration reduction concept is there, ie. the silicon grommets between the hard disks and the hard disk cage, the sound absorption materials on the side walls of the casing, power supply isolation to PC casing, etc....
Don't see this concept in the tripod world, apart from the tripod spikes. There should be vibration reduction/absorbtion features at every interface point ie. camera to plate, plate to clamp, clamp to head, head to tripod, tripod to ground.
Or......we'll just have the micro 4/3 cameras without the penta prism, thus no mirror slap, and no vibrations.....get the G1 guys.....and that $60 tripod...
