Kristen Beebe likes to know who is calling before she answers her cellphone.

The 23-year-old student from Merrimack, N.H., has no patience for nuisance callers who hide behind blocked numbers. About a year and a half ago, she started using TrapCall, a paid mobile app that unmasks private numbers, blacklists unwanted callers and allows users to record their incoming calls.

"It protects me from knowing who is calling if they are harassing me," she says. "It protects me from restricted phone calls because nobody likes to get restricted phone calls, especially if they are telemarketers."

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After signing up "hundreds of thousands" of users in the United States since 2009, TrapCall made its Canadian debut in January of this year. But after only five months, parent firm TelTech Systems Inc. shut down its Canadian service, saying it was pressured to do so by the Canadian Radio-television and Telecommunications Commission, the federal telecom regulator.

The clash with the CRTC highlights a growing tension in the telecom industry. As companies race to bring innovations to market, technology often moves faster than wireless carriers can keep pace, challenging Canada's long-standing commitment to consumer privacy.

Citing a growing need to safeguard subscriber information in the smartphone era, the CRTC is voicing concerns about this emerging issue. The regulator is worried TrapCall is just the first of many controversial apps that will make their way to Canada, including others that allow users to show a false caller identity (see below). Certain users, including victims of domestic violence, social workers and police, "could face threats to their safety" if their restricted caller information is revealed without their knowledge, the CRTC says.

TrapCall sees it differently, saying wireless carriers in Canada and the CRTC prefer to "stifle innovation" rather than give consumers what they really want.

"We would love nothing more than to be able to offer our services in Canada. The decision to stop supporting Canada was not completely ours," but rather that of the CRTC, TelTech said in a statement. "It seemed they were more interested in protecting the identities of those individuals committing acts of harassment than helping victims on the other end of those calls."

The CRTC allowed telcos to introduce "call display" during the early 1990s on the condition they also provide "caller ID blocking" to protect users who need to keep their whereabouts secret. For example, the CRTC cites battered women who place calls from shelters or those who call relatives residing in their former homes by using telephones in locations that could be familiar to their abusers.

Fast forward more than 20 years, and apps like TrapCall are confounding the industry and outpacing telecom regulation. A key problem is that mobile carriers are generally unable to detect when such privacy-circumventing apps are in use by subscribers.

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"The caller and the carrier have absolutely no visibility into what is going on during the use of TrapCall or similar circumvention services," Jim Patrick, senior vice-president of the Canadian Wireless Telecommunications Association (CWTA), wrote in a recent letter to the CRTC.

Also complicating the problem for carriers is that such services often operate from other countries. As a result, the CRTC has written to its U.S. counterpart, the Federal Communications Commission, to examine potential regulatory and technical solutions.

Although the CRTC and carriers managed to scare off TrapCall with tough talk about privacy, other foreign services may not voluntarily leave – especially since such apps are not considered illegal.

According to the CWTA, there are a "number" of existing services or apps that are similar to TrapCall, such as U.S.-based HarassingCalls.com. Moreover, the industry group notes that cheap telecom equipment "all but ensures" the arrival of more privacy-circumventing services.

Caller ID unblocking services can work a couple of different ways. Incoming calls can be forwarded to the service's equipment for caller ID unmasking before they are rerouted to the user. Calls can also be forwarded to a U.S.-based toll-free number to facilitate the display of hidden information.

Carriers are also sounding alarm bells over caller-ID-spoofing services such as TelTech's SpoofCard or the new Burner iPhone app, which allows uses to create an "alias" phone number "in less than 30 seconds."

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Edward Antecol, vice-president of regulatory and carrier relations at Wind Mobile, told the CRTC that Caller ID spoofing services could interfere with Call Trace and emergency services. "Spoofing may also be used to hide toll fraud or hide other illegal activities," he added in his letter.

The CWTA says network upgrades to prevent such call manipulation could take years to deploy and run the risk of interfering with legitimate caller-ID and call forwarding. Carriers want a CRTC-run working group or the Office of the Privacy Commissioner of Canada, which has previously cracked down on Facebook's privacy practices, to probe the problem.

The Office of the Privacy Commissioner says it is continuing to monitor the issue. "Clearly there are privacy issues at stake …The consequences could be extremely serious for some individuals."

The RCMP, meanwhile, said that although such apps may not be illegal, it is always concerned if there is a "risk" to public safety.

Jennifer McGraw, a private investigator in New York City who often works with the city's police on cases involving narcotics and gangs, says the ability to unmask blocked numbers with TrapCall allows undercover agents like her to know if they are being tracked by criminals.

As for the potential of such apps to compromise the safety of abuse victims, she argues that Canada should be educating vulnerable citizens about using technology to their advantage rather than trying to regulate apps. For those who don't want to be found, using a prepaid non-traceable flip-phone (with no GPS) is always a cheap option, she said.

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"Why should I sacrifice technology ... because it may not be good for that other person," said Ms. McGraw.

Controversial apps

TrapCall

Allows users to reveal blocked caller ID information, including names and telephone numbers. Users can also get other features such as the ability to record incoming calls and voice mail transcriptions.

Mr. Number

This U.S. application for Android phones provides caller ID information and lets users block calls and texts from would-be stalkers and annoying telemarketers. It also allows users to customize their own caller ID.

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Spoofcard

Allows users to fake their caller ID information, including their name and phone number. It can also be used to change the user's voice, add background noises and send "spoof" texts.

Burner

This new app gives iPhone users the ability to create extra, disposable telephone numbers for calls and texts. Once a user is finished using the fake number, it can be burned or disposed of without a trace.

Covertcalling

Offers users services such as caller ID spoofing, web calling, call recording and voice disguise. Canadian and U.S. rates can vary, according to the company's website.