And yet . . . Many plants really don’t live on a different continent. If the observation is from the “wrong” area, I think it needs to be held to a fairly high standard. If that observation lacks the traits needed for confident identification, it should be marked as wrong based on range.
Also, fairly often there are subtle clues that let one know that this observation isn’t the plant in question, but explaining would be difficult. The range thing can be mentioned efficiently.
Of course, sometimes plants do show up where they “shouldn’t.” When traits needed for identification are well displayed in the observation, those are fun.