Shilling is illegal in many circumstances and in many jurisdictions because of the potential for fraud and damage; however if a shill does not place uninformed parties at a risk of loss, but merely generates “buzz,” the shill’s actions may be legal.
In marketing, shills are often employed to assume the air of satisfied customers and give testimonials to the merits of a given product. This type of shilling is illegal in some jurisdictions but almost impossible to detect. It may be considered a form of unjust enrichment or unfair competition, as in California’s Business & Professions Code § 17200, which prohibits any “unfair or fraudulent business act or practice and unfair, deceptive, untrue or misleading advertising.”
Radio stations will often have shills (usually front office employees or relative) in the crowd at remote appearances and it is they who will “win” the big prizes (concert tickets, expensive jewelry) while the listeners who show up win nothing.
In 2010, Raphael Golb was convicted on 30 criminal charges, including identity theft, criminal impersonation, and aggravated harassment, for using multiple sockpuppet accounts to attack and impersonate historians he perceived as rivals of his father, Norman Golb. Golb defended his actions as “satirical hoaxes” protected by free-speech rights. He was disbarred and sentenced to six months in prison but remained free on appeal on $25,000 bail.