Easy to sell on, at home or abroad, smartphones are a lucrative target for thieves.

Smartphone theft is believed to account for 30 to 40 per cent of all crime in many cities, according to a study done by the Federal Communications Commission in the US in 2012. A third of Europeans have had theirs snatched.

Thefts in the US almost doubled between 2012 and 2013, from 1.4 million to 3.1 million, according to the magazine Consumer Reports.

No big surprise, then, that consumers feel that if the phones are so darn smart, why can’t owners just shut them down remotely and make them useless to those who take them?

That's the idea behind the so-called "kill switch", in the news this week because the state of California passed the first law in the US making the feature mandatory on all smartphones sold from July 2015. Minnesota already has a kill switch law, but rather than having the feature preloaded and operational by default as in California (owners can opt out if they wish), manufacturers are only required to have it as an opt-in feature, preloaded on the phone or available for download.

The difference is important. Few people go through their phone’s features or the accompanying bumpf, and if they have to download or turn on a feature like this, many won’t.

That’s certainly the case with a lot of iPhones, which now have the built-in Lost Mode within the Find My iPhone feature. This blocks anyone from using the phone who doesn’t have the user ID and password of the person who set up the phone. But users have to enable it.

Still, even the availability of such a feature seems to deter theft. Police in London and San Francisco reported significant drops in iPhone robberies six months after the feature was introduced in iOS 7. In London, thefts dropped by 24 per cent, and in San Francisco, by 38 per cent. And at the same time, there was a major increase in the number of stolen Samsung phones, which did not have similar technology.

Public opinion

Smartphone owners overwhelmingly support the idea of kill switches, according to a study of 1,200 consumers done by a professor at

Creighton University

in the US. Over 83 per cent said they thought having a kill switch would reduce crime, and 99 per cent wanted it as an option from their carriers.

But there are different ways to implement a kill switch. A “hard” switch wipes all data off the phone and “bricks” it permanently, making it useless. A “soft” switch will block the phone, and can delete personal data, but can be reversed (say, if the owner gets the phone back).

California’s new law mandates a soft switch and states it can be a hardware or software solution. All of which would seem a great idea. But some odd bedfellows have opposed the idea of a mandatory kill switch.

Most predictably, the CTIA, which represents the wireless telecommunications industry, opposed it, stating that a new voluntary commitment by manufacturers and network operators – to offer a disabling feature along the lines of Apple’s – was adequate. The more cynical might note that the commitment emerged when it became clear that state laws, and probably a federal law, lay ahead.

The California Chamber of Commerce also dislikes the law, on the grounds that it “stifles innovation of new technologies” – which basically means people were paying for third-party solutions if they wanted one, and now that market is gone.

Compulsory vs optional

Or maybe that’s unfair. The

Electronic Frontier Foundation

also opposed the law, in part because it argued that numerous solutions are already available and people should have the choice to opt for whatever format they want, not a mandated solution.

Their more serious concern, though, is the new law could allow hackers or police to disable phones in some circumstances. The EFF fears the police might opt to do this, say, during protests. But proponents of the Bill said other laws limit when such action could be taken.

In the US, a federal kill switch Bill has begun the journey through the national legislature.

But a similar law doesn't seem likely in Europe. In response to a written parliamentary question in June, European digital agenda commissioner Neelie Kroes said that the commission "has no plans to introduce legislation that would make a hardware kill switch mandatory".

But she added, the telecommunications industry should “introduce a wipe-all functionality that would make it possible to permanently erase all the sensitive data on the mobile handset when needed”.

A kill switch, by any other name.