I've got ferrite blocks on my USB cables and I tend to keep them away from power cables as much as possible, mount power and certainly dew heaters. Ferrite seems to help minimizing noise. As for the rest maybe that's the placebo effect.
But I've been doing it for so long I haven't revisited since. More importantly I have opto isolators between any serial connections and USB. I'm statically charged after a few ports on a windy night and I can blue screen a laptop with my mind powers by just touching the aluminium mount leg.