Wow, that sticker thing is a great idea. I wish we had something like that here. In my city in the states, we don't get paper recycling (we can only do cardboard and bottles free), and our trash costs $5 a bag. So not only do I not have a choice about getting unsolicited bulk paper advertisements, I have to pay the city a premium to get rid of them. It blows.
Write 'Moved' on the "unsolicited bulk paper advertisements" then take it to the mailbox and throw it in there. Now its the post offices problem.
After all, it wasn't addressed to you, so you aren't the lawful recipient so its your duty to write 'moved' on it and put it back in the mail system. I'm sure it'll go to the right place.