Maintaining Sourdough Starter
The vibrations will have an effect: 

On you, because it will be harder to judge the "ripeness" of your refreshed sourdough. You often want to catch the point "just before its starts to go down again" - which will be hard to do when the shaking machine bursts the bubbles all the time.

I doubt that the yeasts and bacteria in the starter will mind - they won't get seasick.