try telling that to a coeliac whose "gluten-free" meal was prepared in the same area as regular pizza, bread, or other wheat containing food
Or someone with a soy-allergy using the same wok that you've just cooked a nice Chinese meal in - inevitably some soy-protein will remain behind to aggravate their allergy - even if the pan has been washed up well.
 - No. You can't use a brillo pad on my well-seasoned wok. It's taken ages to get a proper seasoning on it. And, just for the record, I hate teflon-coated woks. Proper mild steel is best.