Stealth Advertising Hits The Library?

Rob Lopresti writes:\”
You may have heard recent reports about so-called \”stealth advertising,\” in which people called \”leaners\” are hired to tout a product. For example, one might lean against the bar in a crowded pub talking about a wonderful new beer. I may have just encountered the library equivalent. Yesterday I received an email from someone with no obvious connection to my university asking if we owned certain books. Since some of the ones we didn\’t own seemed relevant to our curriculum I looked them up on Google. Here is the page that came up first. Turns out all these books were published by Agora.
Was my correspondent hoping to find the books in order to write a profitable review? Or was there a different purpose in mind?