I worked in Grocery for a while, and ran into the same problem. Including the extra hassle of highly perishable Items. "Eh, I don't really want this gallon of Ice Cream after all. I'll just tuck it back behind this display here in the Baking Aisle, it'll be fine there."

If I take a book out to look at it, I stay right there, and take note of what the two on either side of it were. If I take it away from that section, and then decide I don't want it, it goes back on a shelving cart. Well, except for a few in the SF section that I've taken out bunches of times and I know where they go probably better than some of the Librarians do.