One reassigned number can cost you $1,500. The person who consented to your texts gave up their phone, the carrier handed the line to someone new, and your campaign kept sending. That new owner has standing to sue. Under the Telephone Consumer Protection Act, penalties run $500 to $1,500 per message, and the class actions in this space routinely settle in the millions. The cheapest insurance I know of is checking line type, reassignment, and deliverability before a single message leaves your system.
What the TCPA actually regulates
The TCPA is a U.S. law covering telemarketing, SMS, and robocalls. It was enacted in 1991, well before anyone was sending bulk texts, and the rules have been stretched over the years to cover the channels we use now.
A few things it expects from you:
- Get “prior express consent” before you text or call a consumer
- Apply stricter rules the moment an autodialer or automated system is involved
- Be careful with landlines and reassigned numbers
- Give people a working opt-out and honor it fast
Worth knowing: even B2B messages can trigger TCPA obligations if they land on a personal device without proper authorization. I’ve watched teams assume “it’s business outreach” exempts them. It does not.
The mistakes I see most often
- Sending SMS to landline numbers
- Messaging numbers that have been reassigned or deactivated
- Treating VoIP as somehow outside the rules
- Running old lead lists without re-checking consent
- Skipping the line-type check before outreach
- Ignoring number portability when you track consent history
That last one is sneaky. Consent is tied to a person, not a string of digits, and porting and reassignment quietly break that link over time.
Where phone validation fits
Real-time validation catches the risky numbers before you message them. A single API call gives your compliance team the data points it needs, and you make the suppress-or-send decision before anything goes out.
Line type detection
You find out whether a number is mobile (SMS-eligible), landline (risky for SMS), or VoIP (which gets stricter treatment). This is the first filter, and it removes a surprising amount of risk on its own.
Ported number checks
A number can port to a new carrier after you collected consent. Validation confirms its current status so you aren’t relying on a stale snapshot.
Deactivation detection
Inactive numbers are a liability the moment you contact them, because the message can reach someone you never intended. CheckThatPhone flags deactivated and suspended numbers so you can suppress them ahead of outreach.
Reassigned number protection
Checking for recent reassignment is how you avoid texting the person who inherited a line and never opted in. This is the exact scenario behind the $1,500 example up top.
Litigator scrub
Some of the most expensive TCPA exposure comes from a small set of people, the serial plaintiffs and professional complainants who build cases around being contacted. Our litigator scrub is an opt-in add-on (one extra credit per lookup) that checks each US or Canada number against a database of known TCPA litigators and DNC complainants. On a match it returns the litigator’s name and type, and it rewrites the API’s “action” field to “unsubscribe” so a high-risk number never enters a dialing or SMS campaign in the first place. Scrubbing these numbers before contact is one of the cleaner ways to cut down lawsuit exposure, because you are removing the people most likely to sue before you ever reach out.
If SMS is your channel, the optional landline reachability add-on (also one extra credit per lookup) goes a step further by identifying which landline numbers can actually receive texts, so you keep deliverable numbers without blindly suppressing every landline.
Validate at the point of collection
The cheapest place to fix bad data is the form where you collect it. In practice that means:
- Validate numbers during signup or form submission
- Record line type and porting status with the consent record
- Confirm consent before messaging, especially for VoIP and mobile
- Re-check established customers over time, since numbers change hands
Where to go from here
The math is blunt: $500 to $1,500 per message, multiplied across a campaign, against a fraction of a cent per validation. Validation won’t make you bulletproof, and it doesn’t replace a real consent process, but it removes the categories of risk that are easiest to remove.
Review the CheckThatPhone API documentation to see which fields map to your TCPA workflow, or explore pricing plans and start screening numbers before your next campaign.