No, I think it's more along the lines of they expect you (The end user) and Me (The Supplier) to sign a disclaimer saying that you won't put it to any Illegal use!. Basically its a cop out that protects the manufacturer from any comeback.
The fact that I've now had three replies, almost identical in wording, suggests that they are reading from the same memo circulated directly or indirectly by the R.I.A.A. I don't think it's any secret anymore that the Manufacturers are obviously being "Warned Away" from this type of product.
The difference between "Mrs Jones' Son" downloading the latest Eminem Album from the 'net, and manufacturers producing state of the art hardware for £1000+ is the difference between pirating on a personal scale and those who sell their wares at the Car Boot Sale, Market Stall or the many computer fairs
Basically, the R.I.A.A will try and target the manufacturers of such Hardware, before taking action against young "William Jones" who just listens on his MP3 Player on the way to school.
By Preventing the manufacture of such a unit, they are preventing the D.J from using MP3 Pirated material on a commercial Scale (i.e Making money). Numark and several others have got around this by using a PC for storage, therefore Numark are NOT selling the Hard Drive itself
As for arguing the to$$ with the R.I.A.A then good luck!. Lawyers of Napster tried and failed, So did Audiogalaxy, and from reading some reports around the 'net - Kazaa is about to lose it's battle and close.
A similar battle is raging at the moment, regarding the New DVDR's from Pioneer and co - I suppose hitting the Hardware manufacturer of these devices is a sure fire way of keeping pirating underground, and this also applies to MP3 based D.J equipment.