I've seen this customer complaint numerous times. While I've typically been unable to duplicate it on road test, bopping the dash in the vicinity of the radio often causes it to come on or switch to cd or some other oddity.
To fix it, replace the radio. Unfortunately Hyundai's warranty on the radio is only 3 years/36k miles in the U.S. (for no apparent reason).
Tech... I understand how you feel about the factory radios. Too bad. I sense that there's a very simple reason why this happens -- it's bizzare. Perhaps the physical resistance of the switch (the mechanical toggle) is stiff whereas the actual contacts inside the switch are very loose and can easily short from a bump. Bad bad parts sourcing.
My experience with Korean electronics is that the country's manufacturers can build to whatever quality criterion that they want to select. I've seen both brilliant and dumb products. I don't fully know this radio yet. I'm not sure that I want to. I guess I'll learn (and report back). I am tolerant of "understandable" failures. I detest stupid failures.
Richard
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