Well, just remember, ALL the energy you pump into those speakers has to go somewhere (and your acoustic wattage is flea-powered by amplifier standards): it doesn't just magically dissipate and disappear into damping material, as some seem to believe (I suppose from too much "education" by equipment reviews, and not enough education in physics). Z-man made a different point, I believe; but if your stands are rockin', I'd say you need new stands! Putting much extra mass high in the column is not likely to usefully increase the stability of a proper speaker/stand unit -- more likely, the opposite. I'd load up the base plate, or secure the whole deal to a more stable substrate as necessary, if stability is the issue. Experimentation is called for, especially if you are changing that structure substantially with added mass. Don't believe uncritically stand manufacturers who say casually, go ahead and load it up: That's called marketing to conventional expectations. Once they have the money... it's YOUR problem.
In looking more closely at this issue, most audiophiles with speakers from the "Recommended Components" list (Chinese menu?) will be HEARING less than 2% of the energy delivered from the amplifier. But also heard is the the electrical reactance and the mechanical resonance (forms of energy storage) of the system -- in interaction... just when you don't want to be hearing them. You'd like excesses of these NOT to be launched into the room. With vented/reflex speakers, given typical alignments, this delayed energy can be substantial. A stand which itself is a reservoir for stored energy could be thought of as rather "full up" with vibration. In effect, the energy gradient between speaker and stand is shallower, and, recalling your education in thermodynamics, therefore the system has less potential to do work -- in this case, drain energy away from the speaker cabinet, and especially, its interface with the drive units themselves... most audibly when this is needed most.
Both that interface with the drivers, and the interface with the stands' top plate will be subject to chaotic interactions, a mix of constructive (not in a good way) and destructive reinforcements. Wishful thinking about mechanical diodes won't help you much here. So the issue is not just one of low level smearing, but also the production of other distortions and the loss of information. All of this jumbled energy is quite divorced from the timing of events the voltage source (your amplifier) is trying to impose on the loudspeaker terminals, thus impeding the sense of agility and flow in the reproduced music. Even PRaT-deniers may not like the result. Keeping your stands from overtly "singing" is addressing but a fraction of the problem, and in many cases, may be exacerbating more serious areas of harm. I would surmise that something like this reasoning, conjoined with his long experience and access to the results of advanced measurement techniques, is behind Peter's recommendation. Newton's law of action-reaction must be addressed; but maybe not at the expense of opening up too many other cans of worms.
