What's the word for someone who pretends to buy something from a street-seller, in order to draw other people?

Question

So there's a guy on Oxford Street in London who's always shouting through a PA system from his shop that they're "closing down tomorrow" and all their crappy perfume is on sale. I walk past this place every day and I realised that just as he opens the shop, two people with sullen expressions turn up, say a few words to him, then stand in front of him with fake smiles pretending to offer him money for stuff. It's a typical East End wide boy scam. I know there's a word for people who do this - I'd read it somewhere but have since forgotten it. What is it?

Answer 1

This person is called a shill:

A shill, plant or stooge is a person who helps a person or organization without disclosing that he or she has a close relationship with that person or organization. Shill typically refers to someone who purposely gives onlookers the impression that he or she is an enthusiastic independent customer of a seller (or marketer of ideas) that he or she is secretly working for.

The Oxford English Dictionary notes that this term was first used in 1913, and is chiefly North American. Older terms to refer to these decoys from the OED include:

• stale (now obsolete)
• barnard
• barnacle
• setter
• tumbler