The speech act "Trust Me" often conveys the exact opposite of its literal meaning. This is an example of metacommunication, as analysed by Gregory Bateson and his associates.
When an agency (whether the Home Office or Police, Inland Revenue or Customs and Excise) behaves mistrustingly towards the population, the rational and symmetrical response may be to regard the agency with equal mistrust. However, the actual response is often an asymmetrical one -- to regard the agency with elevated trust.
And when a technology puts forward a claim that it can perfectly detect fraud or impersonation, the rational and symmetric response may be to regard the technology as the fraudulent one. However, the preferred response is sometimes to wrap the technology in a sociopolitical casing, so that it becomes impervious to purely technical criticism. Notions of fraud, fallibility and repression are no longer amenable to technical judgement, but are under political control. This politically encapsulated technology is what is sometimes called a black box. We trust these black boxes because we have no choice.
Building Dynamic Coalitions (Jane Angelis)