Yeah, well..

They probably don't even realize that just because it's a garter snake, that doesn't necessarily mean it's T. sirtalis. I see that a lot. A person will be showing say, a coast garter, and call it "common garter snake. T. sirtalis" It's not. It's a subspecies of "Western terrestrial garter snake" and it's T. elegans, not T. sirtalis.

But, given what very little I know about rat/corn snakes, when I see one I just call it a "rat snake". I have no idea what it's real common name is, or it's actual species name.