STIR/SHAKEN Myths: What It Does Not Fix

Myth 1: STIR/SHAKEN Prevents Spam Labeling

STIR/SHAKEN does not prevent spam labeling. Full stop.

Spam labels — "Spam Risk," "Scam Likely," "Telemarketer" — are applied by carrier analytics platforms that use behavioral data: call volume per number per day, average call duration, consumer opt-out rates, complaint reports from apps like Nomorobo and YouMail, and historical call patterns. STIR/SHAKEN attestation is one input to those models. It is not a veto.

A caller ID with A-level attestation that makes 800 short calls in a single day will get labeled. The attestation confirms you are who you say you are. The behavioral data says you are acting like a high-volume robocaller. The analytics engine treats the behavioral signal as more predictive than the attestation signal at that volume level.

What STIR/SHAKEN does is raise the threshold before labeling occurs. A-level attestation gives you more behavioral headroom before a label triggers. It does not give you unlimited headroom.

Myth 2: STIR/SHAKEN Applies Globally

STIR/SHAKEN is a US and Canadian protocol. It is not operative in the European Union, the United Kingdom, Australia, most of LATAM, or any of the other 31 markets covered by UnlimCall's outbound network.

The EU has been developing its own framework (the ETSI TS 103 479 standard), but implementation is fragmented and not yet universally deployed across European carriers. The UK has its own Calling Line Identification (CLI) authentication initiative. APAC markets have no equivalent framework with meaningful penetration.

For outbound teams running multi-country campaigns, STIR/SHAKEN is a US and Canada story. Answer rate optimization in Germany, France, the Netherlands, or the Philippines is driven by different variables: local number presentation (displaying a number with the correct national prefix), carrier relationship quality, and time-of-day matching. Applying STIR/SHAKEN logic to non-US campaigns will lead you to optimize for the wrong lever.

Myth 3: Getting STIR/SHAKEN Means Your Provider Has Filed With the FCC

These are two separate things. STIR/SHAKEN is a technical standard — a cryptographic signing protocol. Filing with the FCC's Robocall Mitigation Database is a regulatory requirement. A provider can implement the STIR/SHAKEN technical protocol without having a current, compliant RMD filing. A provider can have a valid RMD filing that covers only a portion of their infrastructure.

When evaluating a SIP trunk provider, you need both: the technical capability to sign calls, confirmed by asking what attestation level your specific calls will carry, and the regulatory standing, confirmed by looking up the provider in the FCC's public Robocall Mitigation Database.

See the full breakdown of the RMD requirement and what it means for your call path.

Myth 4: STIR/SHAKEN Verifies That Your Call Is Wanted

STIR/SHAKEN verifies that you are who you say you are. It says nothing about whether the called party wants to receive your call.

This distinction is important because some outbound teams interpret STIR/SHAKEN implementation as a consent signal or a compliance safe harbor. It is neither. A fully attested call to a number on the National Do Not Call Registry is still a DNC violation. A fully attested call to a consumer who has not provided express written consent for a prerecorded message is still a TCPA violation. STIR/SHAKEN is a call authentication framework, not a consent framework, and not legal advice.

Myth 5: Signed Calls Cannot Be Flagged by Carrier Analytics

Carrier analytics platforms — CNAM databases, third-party labeling services, and the major carriers' proprietary systems — operate independently of STIR/SHAKEN validation. They can and do label A-level signed calls when behavioral signals warrant it.

The interaction works in one direction: a lack of STIR/SHAKEN signing (C-level or unsigned) is a negative signal. Full signing (A-level) is a positive signal. But the positive signal from A-level attestation does not override a strong negative behavioral signal from the call pattern data.

This is why the most common advice to get attestation, then stop worrying about it is wrong. Attestation is a foundation, not a ceiling. You build on it with caller ID management, reasonable daily call volumes per number, appropriate handle times, and list hygiene. The answer rate framework describes how these layers interact.

Myth 6: Your SIP Trunk Provider Controls Whether You Get STIR/SHAKEN

Your provider controls whether calls are signed and at what level. They do not control how the attestation signal is interpreted and acted upon by the terminating carrier. T-Mobile, AT&T, and Verizon each have their own analytics platforms, their own labeling criteria, and their own display logic. An A-level call on T-Mobile may display differently than the same A-level call on AT&T.

This means that STIR/SHAKEN optimization is necessary but not sufficient. The goal is to present the best possible attestation level — which is fully in your control through your SIP trunk provider choice — and then manage calling behavior to keep behavioral scores clean, which is also in your control. The display decision at the handset is not in your control. You can influence it; you cannot own it.