March 25, 2026
Call Flagging Activity Is on the Rise — Here’s What You Can Do About It
Robocalls are still one of the biggest nuisances in 2026, but phone companies like T-Mobile are fighting back. The problem is that legitimate businesses get caught up in this crossfire. Overly aggressive algorithms flag calls, potentially leading to lower answer rates. Here’s how you can prevent your numbers from being affected by call flagging activity.
T-Mobile Aggressively Ramps Up Robocall Protections
New data from Caller ID Reputation (CIDR) reveals that T-Mobile has increased the amount of numbers it flags. This increase in flagging activity is largely due to more aggressive network-level protections. Take the carrier’s Scam Shield feature, for example. It uses AI, machine learning, and data from the branded call solution company First Orion to analyze call behavior in real time and scan calls at the network level. This is different from more basic security tools, which simply rely on customer reports and call-blocking apps to reduce robocalls.
Scam Shield, which works automatically on T-Mobile devices for no additional cost, flags call patterns commonly associated with robocallers, such as high call volumes, short call durations, and frequently dropped calls. While it’s a great idea in general, these same patterns can apply to genuine businesses that rely on outbound calls to generate leads. As a result, T-Mobile might flag your numbers as spam or block them entirely, making it difficult to engage with new customers.
Increase in Call Flagging Behavior Among Carriers
It’s not just T-Mobile that’s increasing the number of flags. CIDR has discovered that other carriers are enhancing their call-filtering algorithms, resulting in more businesses receiving unfair call labels like “spam” and “scam-likely.”
While it’s not known how many companies have been affected by these recent changes, some are seeing their answer rates drop significantly. Getting customers to pick up the phone has never been harder.
Carriers are just part of the problem here. According to a recent report from CIDR, 50% of all call flags in 2025 came from consumers marking calls as spam, typically through call-blocking apps and data aggregators. Again, real business numbers are often flagged during this process, leaving them with few options for customer outreach.
Effects of Carrier Call Flagging
Carriers like T-Mobile have good intentions. U.S. consumers received 52.5 billion robocalls in 2025, only a 1% drop from 2024, so it’s no surprise that carriers are taking action. They also have to do so by law. Regulations from the Federal Communications Commission (FCC), such as the TRACED Act, require providers to actively track and block robocalls or face hefty fines for non-compliance.
However, the trouble is a lack of consistency, with each carrier relying on its own individual algorithms to identify nuisance calls. This can lead to inconsistent call labeling across the board. For example, your calls might connect to customers on Verizon but receive “Spam Risk” flags on AT&T. These discrepancies leave businesses wondering why their answer rates are dropping.
CIDR recently found that some numbers never receive call flags by any carrier during their entire lifecycle, while others get flags every single month. However, it’s important to note that this could be the result of dialing behavior as well as carrier algorithms, with poor calling practices, such as exceptionally high call volumes, potentially leading to negative flags.
Device Cloud Audits Caller IDs Across Networks
CIDR’s Device Cloud is a service that lets you audit your caller IDs across real networks and devices. The result? You can audit your call flags across different networks and devices to identify those that jeopardize your outbound campaigns. Then, you can use our Remediation Managed Services (RMS) to regain control over the numbers your agents rely on.
With complete call optimization platform, maintaining accurate caller IDs is simple. You can improve due diligence, routinely scan your numbers, and promptly remediate issues.
Steps You Can Take To Mitigate Call Flags
Software alone can’t stop carriers and analytics engines from negatively labeling your numbers. While it’s impossible to eliminate flags entirely, there are steps you can take to protect your numbers. Your contact center must adhere to strict data hygiene requirements and comply with dialing behavior standards.
For example, your agents should only call customers at appropriate times based on their time zones and limit the number of calls to the same customer. You’ll also want to check numbers against the Reassigned Numbers Database (RND) and Do Not Call Registry (DNC) to make sure you’re calling the right person and aim for an A-attestation rating, which can increase the chances of your calls getting through.
Other tips include segmenting your outbound campaigns to target customers who are actually interested in your products and services. Finally, monitor call flags proactively, audit caller IDs across devices and networks (CIDR’s Device Cloud helps here), and address negative call flags promptly.
How CIDR Can Help You Deal With Call Flagging Activity
CIDR’s suite of outbound call management tools helps your business identify, manage, and mitigate call flags. Our call optimization suite can help your business mitigate call flags.
- Device Cloud: You can audit caller IDs across real devices and networks.
- Phone Number Monitoring: With this feature, you can use daily scans to quickly identify call flags.
- Remediation Management Services (RMS): This service lets you submit remediation requests to carriers and analytics engines.
- DialRight™: If you want to improve data hygiene, DialRight audits call lists for you.
- Attestation Tester: Checks your phone numbers’ attestation ratings directly through CIDR.
With these services, you can reduce the likelihood of flags and blocks and continue to have conversations with customers.
Contact CIDR today to learn more about tools that give you more control over your outbound numbers.
