They do, I don't know if they do at every airport, but they do. The problem is that most people don't want to bother. But i have heard at least 4 times or so at different airports when someone gets "caught" with something, they offer to point you to the counter where you can buy a postage paid envelope to ship it back. Everytime I have seen this, the "victim/offender" gets an attitude, says "forget it" and storms through the security.