Yes, i think too it's a hardware problem. I even believe it has nothing to do with electrostatics or things like this. Its a pure mechanical problem. The vibrations of the amp makes the knobs move.
Usually I try to prepare my presets with fuse at home. I Dont like to have a computer connected all the time. If I have to change s.th. concerning the effects on a gig I save immediatly, turn back to Zero and re-choose the same preset again. So I must not fear an unexpected "Vintage Tremolo" in the middle of a solo.
Of course this cannot help against the unwanted swiching of presets itsself, what also happend to me several times. No risc, no fun
Serious: I would surely pay 50 Euros more for the same Mustang with better Hardware. And this are not only the self moving controls, its too the small Aux and Phones Jacks, the delicate small USB Plug - and maybe an effects out/in to be able to use a Looper in the used way and a reachable middle-tonecontrol ... Ok, the last two points are OffTopic here...