Except you can use obscure dead tree books as sources and no one will take the effort to check whether the book indeed says so. Use a book obscure enough -- especially in a non-English language -- and it becomes almost impossible to execute said check.
It depend so. The amount of trust I want to give. By citing an obscure book I can judge the fact "hm, that book sounds obscure, why isn't there some other source?" and then decide how much weight I give to it.
And if I don't have the book at hand I can identify the person who added the citation and can see what other edits they did to judge their domain knowledge.
But in case they do you can ask your other well established sleeper account for a book reference then reply a few days later with a: This is what I found posting. Then when asked you can point to yourself and say I've asked him. Do a conversation with yourself weighting how a book is hard to validate vs how important the information is to the article.
