Guide

Fake webinar registrations

Registration is the number the whole programme is judged on, which makes it the number most worth distrusting. Here is what pads it, what that costs, and how to stop it.

Updated July 2026 · 8 min read

Event and webinar funnels are attractive targets for a reason: the form is public, promoted, often paid-for, and it hands back something useful the moment you submit it. A confirmation email proves the address is monitored, the calendar file and joining link have resale value, and the form itself asks for name, company and role — exactly the fields worth harvesting.

What it does to your numbers

The damage is analytical before it is financial, and it is unusually misleading because it moves two metrics in opposite directions.

MetricWhat fakes do to itWhat teams usually conclude
RegistrationsInflated"The campaign worked"
Show-up rateDepressed — bigger denominator"Our reminders are weak"
Cost per registrationLooks lower"Spend more on this channel"
Post-event pipelineUnchanged"Webinars do not convert"

Every one of those conclusions is wrong, and the last is the expensive one — a channel gets cut on evidence that was contaminated at the form.

The reminder-sequence trap

Because a falling show-up rate looks like a nurture problem, the standard response is more reminder emails to a list that is partly fake. That increases send volume to unengaged addresses, which is itself a deliverability risk — see email list bombing for why engagement signals matter to your domain.

The direct costs

Spotting them

Judge arrival rather than plausibility — see bot leads in your CRM for the same signals applied downstream.

Stopping them

  1. Hygiene first. Server-side validation, a signed timing check, rate limiting per IP and per address, a properly hidden honeypot. See stop contact form spam for the ordered list, and stopping form spam without a CAPTCHA for what each method actually catches.
  2. Screen disposable domains at submission, not at export. Score them rather than hard-rejecting — some real attendees use alias services.
  3. Do not send the joining link before confirmation on high-value events. It removes the payload that makes registration worth automating.
  4. Report attendance against verified registrations, so a fake cannot move the ratio your programme is judged on.
  5. Suppress the conversion event for flagged registrations, or your ad optimiser keeps learning from them.

What we would not do is add a CAPTCHA. Registration is a high-intent moment you have usually paid to reach, so friction there is among the most expensive on your site, and convincing fake registrations come from tooling a challenge does not reliably stop. Network-level protection at your CDN is a different layer and is fine.

Where SpamKill fits

SpamKill scores how the registration was filled in rather than what it says, so automated signups never reach the platform, the sequence or the seat count — at 99.9% accuracy across more than 100M+ submissions screened for 1,500+ businesses, with no challenge on the form you paid to get people to. Flagged registrations are held and reviewable rather than deleted, so a real attendee is never quietly lost before an event. See also SpamKill for high-volume funnels. From $29/month with a 30-day free trial, no credit card.

Frequently asked questions

Why would bots register for a webinar?

Usually for the confirmation email rather than the event. A registration confirms the address is live and monitored, often delivers a calendar file and a joining link, and sometimes carries a discount code or gated asset. Registration forms are also unusually rich targets because they ask for name, company and role — useful data to harvest.

How do fake registrations show up in my numbers?

As a registration count that looks excellent and a show-up rate that looks terrible. Because attendance is measured against registrations, padding the denominator drags the ratio down, and teams then spend the next quarter optimising reminder emails to fix a problem that was never about reminders.

Do they cost money directly?

Often yes. Webinar platforms bill by registrant or seat on many plans, reminder sequences bill per send, and enrichment tools bill per lookup. A few thousand fake registrations can consume a meaningful share of a seat allocation before anyone joins the call.

Can I just clean the list before the event?

Partly, and it is worth doing — remove disposable domains and obvious duplicates. But cleanup happens after the platform counted the registrant, after the automations fired and after the enrichment ran, so most of the cost is already incurred. Blocking at the form is much cheaper than filtering afterwards.

Should I put a CAPTCHA on a registration form?

We would not. Registration is a high-intent moment you have usually paid to get someone to, so friction there is expensive, and the tooling producing convincing fake registrations is not reliably stopped by a challenge anyway. Judge how the form was filled in instead.

Protect the registration form

Paste your registration form HTML into the Form Transformer and get the protected version back — no signup, no card, nothing to install.

Open the Form Transformer