Do publishers mess around with the used-textbook supply?

I”ve been sifting through the dozens of responses I’ve received from professors in our Public Insight Network who are talking about what they’re willing to do to keep textbook costs down.

I found the tidbit below from University of Minnesota – Duluth math and statistics professor Chad Pierson a bit unsettling.

Hardball capitalism — or urban myth?

I know that on the demand side, we as instructors should control the market. But a bookstore clerk once told me that the publishing companies buy used texts off the internet and shred them to ensure demand on the newer editions.