How this is unethical, however, is a matter of dispute:
- It might be a hoax. The guy who put it on Facebook swears he saw it in a book store. If not, he’s lying.
- If this was done by a book store staff member as a gag, it’s disrespectful to the book’s market. Such irony is misplaced in a book store, when a religious book is the prop. I’d call it a firing offense.
- If this is false advertising, that is also unethical.
And if someone slapped the sticker on the wrong book and isn’t educated enough to realize that this is one book that can’t have a signed copy, that’s unethical incompetence and ignorance for a book store employee.