This could be solved by allowing a three-way choice. I.e. “Yes, it is that species.” vs. “No, it is definitely not that species.” vs. “I don’t know.”
It seems it might be useful to make these distinctions. I know I would select both “No” and “I don’t know.” frequently. I think it would help the community reach an ID consensus too, it would be less abrasive, more educational, better at communicating our intent and knowledge, etc.