Weights on a preamp

I have an Art Audio VPL MK2 preamp. I think, if I remember correctly, that Joe Fratus of Art Audio mentioned that some people place a weight on the top of the unit, which I assume is to dampen vibratory activity with weight pressure and its gravity. I have heard of this with speakers, but preamps? Is this geeky overkill, or does it really work? What are the opinions on this weighty matter ?