Ask HN: Should you reply STOP to unwanted texts?

Hacker News Discussion ↗

Unwanted SMS, especially political and scam texts, are prompting people to ask whether replying with “STOP” actually helps or just confirms their number to spammers. Commenters note that in the US, carrier rules and platforms like Twilio often honor STOP for legitimate, programmatic campaigns and short codes, but that shady operators and criminals largely ignore it, rotate numbers, or use replies to validate active targets. Many instead recommend blocking senders, using carrier/OS spam tools and reporting mechanisms like 7726 and FTC/FCC forms, while reserving STOP for texts from organizations they knowingly interacted with.

When to Reply STOP vs Ignore

  • Many argue: never reply to unsolicited texts. Any response (including STOP) confirms a live, engaged number that can be resold or targeted more.
  • Others: reply STOP only to texts from organizations you knowingly gave your number to (banks, stores, password-reset services), not to obvious scams.
  • Some report STOP reducing spam from “semi-legit” senders (brands, political campaigns), but not from pure scammers.
  • Several note that with spam using rotating numbers, STOP only affects that one sender/number and is of limited value.

How STOP Is Actually Handled

  • For US short codes and programmatic SMS, carriers and vendors are generally required (by CTIA/TCPA rules) to honor STOP as an opt-out.
  • Disagreement on mechanics:
    • Some claim carriers intercept STOP at network level.
    • Others state STOP is delivered to the sender’s platform, which must comply or risk losing carrier access.
  • Not all platforms honor STOP; some political/VOIP/marginal providers and certain retailers keep sending despite confirmations.
  • Edge cases: “UNSTOP”/“START” sometimes required to re-enable 2FA or shared short codes; past STOP can silently break verification flows.

Security & Privacy Concerns

  • Several warn that simply opening texts or emails can be risky (historical zero-click exploits on iMessage/Outlook).
  • Concern that URL previews, read receipts, and RCS features can leak that a message was viewed.
  • Core advice from this camp: don’t interact at all; delete or block.

Political Spam & List Sharing

  • US political texts are pervasive and often legally exempt from anti-spam rules.
  • Donating once or giving a number to any campaign can result in years of cross-shared harassment across many committees and PACs.
  • Some users now refuse to donate or vote for candidates who spam, or threaten to support opponents to get removed.

Reporting & Countermeasures

  • Common tactics:
    • Use OS/cellular tools: block numbers, “Report Junk,” forward spam to 7726 (US/UK), enable spam filters, silence unknown callers.
    • Report to FTC/FCC and carriers; a few pursue TCPA litigation for statutory damages.
    • Lookup carriers (e.g., freecarrierlookup-type tools) and file abuse reports with underlying SMS platforms.
    • On iOS/Android, use local SMS filters or keyword rules (especially for political/spam domains); opinions differ on effectiveness.

International & Miscellaneous

  • Behavior differs by country and carrier; in some places STOP is not enforced or is routed through ad companies.
  • Many lament that OSes don’t provide stronger, user-configurable SMS spam filtering comparable to email.