There may be another side to the story that the employees do not know about....
Most bookstores have the right to return books that do not sell for a credit. There is often not a time limit. I'm sure that you can imagine that after sitting on a shelf for a year or two and being abused, that the publisher cannot really sell them once they are returned. In fact, when I worked at a bookstore, many of the newer titles were not worth returning, so to prove that we did not sell them, we were to rip the cover off, send that back and toss the book in the garbage. With magazines they only wanted the name cut out from the front cover.
But I's wandering here....
My understanding (I read this somewhere), was that Black Sparrow Press had a special deal with the bookstores (one that no other publisher had). Once the bookstore bought them, they owned them. There were no returns. If this is true, it speaks to the power of Bukowski's appeal, the savyness of John Martin and would explain why the chain bookstores would not want them on the sales floor. They may have wanted to keep them in sellable condition. Now that Harper Collins owns the rights, they can let them get destroyed by browsers and then just return them when they are done with them.
If this is the case, I cannot imagine the chain store management explaining this to the clerks or them explaining it to the customers. It would be easier to say that they were the most stolen books.
Bill
p.s. When I worked in a bookstore the most stolen books were porn mags, but that was before the days of free porn on the 'puter.