Doesn't oxidation occur over time? I'd argue that if more beans were put through it it'd be less likely to corrode as the beans would be exfoliating the burrs more regularly?
In electrical testing, there are 3 categories of fault, C3, C2 and C1, meaning minor problem, serious problem and "someone may die" problem. Very rarely do these get better over time, only ever worse, lack of use as a defence just isn't a defence.
Personally, if I forgot/neglected to do something important 3 times, I'd hold my hands up and admit fault if it all went wrong. Yes a coffee grinder is designed to grind coffee, but a frying pan is designed to fry stuff and even a stainless steel one will look a mess if you can't look after it as the manufacturer recommends/common sense dictates.