Ostensibly, it’s the app that helps keep users safe by suggesting the safest route home. The response, however, has been very different to what its creators presumably intended, with accusations that the app comes across as prejudiced and scaremongering, not to say snobby as hell.

SketchFactor, available at present only in the US on iOS, is a crowdsourcing app in which users are encouraged to share their observations and experiences of different city neighbourhoods, which are then given a rating as to how “sketchy” they are.

Critics say this is the technological equivalent of people crossing the road to avoid black youths, or turning their noses up at a less salubrious zip code. It does feel rather like the app that George Zimmerman might have invented – or your grandma.

In reality, however, the app is the work of Daniel Herrington and Allison McGuire, and the opprobrium directed towards the pair has only increased with a cringe-inducing PR shot of the two, back-to-back and smiling, like a couple in a real estate advert.

Here’s an example of why some people are upset:

Users on Twitter have fought back against the implicit idea that, god forbid, not everybody lives in Wisteria Lane and sometimes people spraypaint subway cars:

SketchFactor has responded with a statement acknowledging the negative press on its website:

People are entitled to their opinions. That’s legit. But slamming SketchFactor without having a conversation is unprofessional.

Guardian Cities has contacted SketchFactor: we’ll let you know if we hear back.

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