How can you verify event attendance without a scanner?

Validate check-in against a geofence drawn around the venue, using the attendee's own phone. The device reports both a position and an accuracy radius, and both are used in the decision, so a confident reading outside the boundary is treated differently from an uncertain one.

Is GPS check-in accurate enough indoors?

Indoors, phones fall back to wifi and cell positioning, which widens the reported accuracy radius rather than producing a confidently wrong position. Draw the geofence generously for indoor venues; the trade is between admitting someone just outside and rejecting someone genuinely inside.

Why is RSVP data unreliable for attendance?

An RSVP records an intention, made days earlier, with no cost to changing your mind. No-show rates for free events are routinely high, so staffing and catering planned against RSVPs are planned against a number that was never a measurement.

How to verify event attendance without scanners or badges

A ticket scan proves a code was presented at a door. A geofenced check-in on the attendee's own phone proves a person was inside the venue. The second needs no hardware, no queue at a scanning desk, and keeps working after the doors close.

What each method actually proves

These are not three versions of the same measurement. They answer different questions, and the gap between them is where staffing decisions go wrong.

Method	What it proves	Fails when
RSVP list	Someone intended to come, days ago	Always, to some degree — intention is free to change
Ticket scan	A valid code was presented at a door once	Codes are forwarded; one person scans four tickets; nobody rescans on leaving
Badge / NFC tap	A badge passed a reader	Badges are shared or left on tables; needs hardware at every point you want to measure
Geofenced check-in	A device was inside the boundary, to a stated confidence	Attendee has no app, no signal, or declines location

Why RSVPs cannot be used as attendance

An RSVP is a promise made days earlier at no cost. For free events especially, the gap between promises and arrivals is wide enough that planning staffing, bar stock or catering against it means planning against a number that was never a measurement in the first place.

The practical damage is not the headline number. It is that the error is unknown and inconsistent: you cannot correct for a no-show rate you do not measure, and it moves with the weather, the day, and the lineup.

How geofenced check-in works

The organizer draws a boundary around the venue. When an attendee checks in on their phone, the device reports two things: a position, and an accuracy radius — the phone's own estimate of how sure it is. Both go into the decision.

Using only the position is the common mistake. It treats a confident reading and a wildly uncertain one as equally trustworthy, which produces exactly the wrong behaviour indoors, where accuracy degrades.

What good looks like

Draw the boundary to include the queue. People waiting outside are at your event. A fence tight to the walls rejects the people about to walk in.
Let accuracy widen the benefit of the doubt. A reading with a 100-metre uncertainty inside a 30-metre venue is a phone indoors, not evidence someone is elsewhere.
Do not block anyone at capacity. Refusing check-in removes that person from your own record while they are still walking in. See knowing when a room is over capacity.
Count crew separately. They are bodies in the building for safety, and not attendees for measurement.

Where it fails, honestly

It needs the attendee to have the app and allow location. This is a sample, and a good one, but it is not a turnstile count and should never be handed to a regulator as one.
Dense urban venues degrade positioning. Tall buildings and basements widen the accuracy radius, which is why the radius has to be part of the decision rather than ignored.
It proves a device was present, not a person. Every method here has an equivalent limitation — a scanned ticket proves a code was presented, not who presented it.

What it gives you that a scan does not

A scanner is a gate: it fires once, at one place, then stops being useful. A geofence is a boundary that stays true for the length of the event, which is what makes a live count possible at all — how full the room is now, rather than how many people arrived at some point tonight.

That is the difference between a number you report afterwards and a number you can act on while the doors are open.

Last reviewed August 2026. If something here stops being true, it is a bug — tell us.