Your comment, on the other hand, does not accurately describe the relevant law.

PUC 7908 states that "If a governmental entity reasonably determines that an extreme emergency situation exists that involves immediate danger of death or great bodily injury and there is insufficient time, with due diligence, to first obtain a court order, then the governmental entity may interrupt communications service without first obtaining a court order as required by this section."

Your statement that PUC 7908 prohibits interruption only in hostage or barricade situations is incorrect; those are referred to in PUC 7907, which discusses cutting phone lines. PUC 7908 involves cutting cell service, and is more broad - it uses the language quoted above.

I could easily see this applied to a protest; police say a protest will lead to looting (e.g. Ferguson), perhaps they even see plans for flash mob robbery on social media. On the basis of this, they brick every phone in a protest zone, undercutting protest organization and limiting demonstraters ability to film police abuse on smartphones.

I do not know what the legislators intended; maybe they don't know about the issue, maybe they don't care, maybe they think this is an adaquete solution and are wrong. I don't try to define their intent here, I'm simply trying to point out a very real problem with this law.

(C) "Interrupt communications service" does not include any interruption of service pursuant to an order to cut, reroute, or divert service to a telephone line or wireless device used or available for use for communication by a person or persons in a hostage or barricade situation pursuant to Section 7907. However, "interruption of communications service" includes any interruption of service resulting from an order pursuant to Section 7907 that affects service to wireless devices other than any wireless device used by, or available for use by, the person or persons involved in a hostage or barricade situation.

More importantly, this subsection certainly doesn't change the fact that your above description of 7908 as a law that "prohibits interruption of communication by law enforcement in anything other than a hostage or barricade situation" is completely inaccurate.

It is broader, and could apply to protests if there is a claim of imminent risk of great bodily harm, as police have been claiming for the last week during mistreatment of protesters and journalists in Ferguson.

The entire reason for attempting to pass a law like this is because it's assumed it would be illegal for the police to do it without a law passed specifically saying they're allowed to (Like everything else). If the police in MO did this, they'd have tons of lawsuits against them.

It would still likely result in lawsuits anywhere it was used regardless of the law.

The bill includes restrictions on the government at the level that falls within the jurisdiction of the law. The argument is what about jurisdictions that have no such law nor restrictions and take advantage of the existing hardware feature?

If we're talking Federal law then what you say makes sense, but as far as I know this is about a state law.

But keep in mind absent this law there is no mandatory kill switch in phones in the first place, so the possibility of police use en masse aginst protesters - regardless of whether law permits such co-opting or is silent on the subject - becomes much lower.

"The smartphone shall, during the initial device setup process, prompt an authorized user to enable the technological solution. The technological solution shall be reversible, so that if an authorized user obtains possession of the smartphone after the essential features of the smartphone have been rendered inoperable, the operation of those essential features can be restored by an authorized user."

And section 2.2:

"An authorized user of a smartphone may affirmatively elect to disable or opt-out of enabling the technological solution at any time. However, the physical acts necessary to disable or opt-out of enabling the technological solution may only be performed by the authorized user or a person specifically selected by the authorized user to disable or opt-out of enabling the technological solution."

And Section 1.g:

"As a result, the technological solution should be able to withstand a hard reset or operating system downgrade, come preequipped, and the default setting of the solution shall be to prompt the consumer to enable the solution during the initial device setup. Consumers should have the option to affirmatively elect to disable this protection, but it must be clear to the consumer that the function the consumer is electing to disable is intended to prevent the unauthorized use of the device."

Personally, as long as those things are both true and implemented correctly I don't see any reason to argue. If disabling it on the phone doesn't work, everybody with those phones could sue the company making them (If they live in CA...). Outside of CA, they could legally sell phones with kill-switches inside with no disable option, but that's legal to do right now anyway so this law wouldn't change that. And, seeing as in CA it'd be illegal to sell them without the disable option, I don't see why they would spend the extra money to design a version without a disable to sell outside of CA, so it probably wouldn't change things much.

the police there will be free to do whatever they want with this switch.

Why, do they not have any law about interfering with communications in MO? If not, why hasn't cellphone service been shut down there already?