I read 2600 once in awhile as it usually has a few decent articles on barriers and how to get around them. Its also nice to see what people are using or playing with. In the recent Winter 2006-2007 issue there was an article titled “Library Self-Checkout Machine Exploit”. If you get a copy I suggest browsing through it.

The gist is that because on some (all??) machines the barcode is scanned from the top and the book desensitized from the bottom you can abuse it to desensitize books your not checking out (stack the books). You then take the books that are checked out which of course sets off the alarm. You have a receipt that shows them checked out and eventually get out. Someone else takes the desensitized books out separately.

Probably not an issue with RFID but something to look out for if you have the machines and people start setting the alarm off with a bunch of checked-out but not desensitized books.

This is basic enough that it has probably been posted elsewhere many times before but figure I should post it just in case so libraries are aware.