Not that it happens frequently, but if it does and your application scenario is critical, how do one knows if say the corrupted data is a minor color component

Not that it happens frequently, but if it does and your application scenario is critical, how do one knows if say the corrupted data is a minor color component in an image or frame of a movie, or a variable in a spreadsheet cell buried somewhere? Would anyone notice? If a bitflip happened in a location containing the target address of a jump then the software or the OS would likely bomb immediately telling there's something wrong somewhere, but (unfortunately) there are subtle errors that can go unnoticed until it's too late. ECC is meant to protect also from those.