A guilt sticker (or usually a packet of them) is included in non-profit promotional mailings designed to make the recipient feel guilty in the event that he/she does not donate. They often have photos of symbols (e.g. kittens) the recipient is likely to identify with, or are printed with the recipients address to serve as return-address labels for letters, or both.
"I put this Sierra Club guilt sticker on my notebook because I thought the wolf was cool. Now every time I see it I feel terrible that I didn't donate."
by farenorth September 29, 2014