Usually, if I ID something that I’m not sure about or there’s not enough information in the photos to be sure, I will add a comment describing which other taxa it could be or what additional info is needed. That way others can gauge how much they trust my IDs. But I would rarely say I’m 100% certain since there’s a lot of variability and nuance in plant ID.
But plant and insect ID seems to be a lot less contentious than vertebrate ID.