curse of the phone book

we get a lot of phone books on our doorstep. we don't even use them so today we took the four that we had in the apartment, plus the one that's been sitting outside for the past month and a half down to be recycled. this was about 10 am. when josh left for work at 12:30, what was sitting outside our door? TWO PHONE BOOKS!!! how did they know we just got rid of 5? we'll just leave this one outside so they know we don't need anymore.