If this is a danger from "snake oil" of this type, it'd be from the other side, where artists are intentionally tricked into believing that tools like this mean that AI isn't or won't be a threat to their copyrights in order to get them to stop opposing it so strongly, when in fact the tool does nothing to prevent their copyrights from being violated.

I don't think that's the intention of Nightshade, but I wouldn't put past someone to try it.