Here is an ambient ad from New Zealand for fair trade All Good Bananas:
Using the "Audio Spotlight," they were able to communicate to one shopper in a crowded supermarket with a narrow high-frequency beam of sound that was transmitted over a floor sticker instructing shoppers to "listen to your conscious." When someone would stand over the sticker they would hear a private message:
"Hi you can hear me, can't you?
You're the only one.
Look around. No one else can. See?
You know who I am? I'm that inner voice. I want to talk to you about something.
Fair trade. Look at them all. Those bananas in front of you.
Which should you buy? I know. And you do too.
They're All Good bananas. They're the only fair trade ones.
So you now know which ones to choose. Make a good choice."