Knowing that the data is unreliable is something already. Then, you can apply heuristics. And, if there is a systematic error, you should be able to detect this

Knowing that the data is unreliable is something already. Then, you can apply heuristics. And, if there is a systematic error, you should be able to detect this, eventually. (E.g., what is the unreliable series, what is the bug and when is it triggered?) But, yeah, this is why I wrote "at least".