USB 2.0 is specified to have a bit error rate of no more than 10E-12 (ten to the minus twelve). Any USB connection that has a higher BER is out of spec and hence defective. Copying to a USB Harddisk would become a hit and miss process, if this spec would not hold in reality.
With a signal of 24bit/96kHz that BER would amount to one bit error every 1’206 hours. It is highly unlikely that after >1k hours of listening you will notice 1 bit wrong.
If the “analogue” noise causes more errors than that (which would need to be the case to give the claims raised here any plausibility) then the system is not designed to meet specs.
This does NOT mean that analogue noise cannot propagate along a USB cable and influence analogue circuitry in the equipment further down the line. But the disturbance is certainly not caused by digital errors (again, unless the equipment is faulty).
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