Non-PRO English to Portuguese Art/Literary Slang everyday language

Olá.
Estou buscando uma tradução para o português da gíria "shill".
Tenho esta definição do Answers.com:
"One who poses as a satisfied customer or an enthusiastic gambler to dupe bystanders into participating in a swindle."

E outra mais detalhada da Wikipedia:
A shill is an associate of a person selling goods or services or a political group, who pretends no association to the seller/group and assumes the air of an enthusiastic customer. The intention of the shill is, using crowd psychology, to encourage others unaware of the set-up to purchase said goods or services or support the political group's ideological claims.

Desde já, muito obrigada.
Louise