Geofencing Attendance: Does a Location Check Stop Fake Check-Ins?
A location check catches people checking in from outside the venue. Here is how it works, how accurate it is indoors and how to set it up fairly.
Geofencing attendance means checking that a phone is at the venue when someone checks in. It closes the last easy gap in QR attendance: a person in the room sending a live photo of the code to someone outside, who scans it within seconds.
How it works
- The organizer sets the venue location and a radius, for example 150 metres.
- When someone checks in, their phone is asked for its position.
- The system measures the distance to the venue and records the result: at the venue, off-site with the distance, or location unclear.
Only the result needs to be stored, not the coordinates, which keeps the data you hold to a minimum.
How accurate is phone location indoors?
Outdoors, phones are usually accurate to within a few metres. Indoors, in basements or in large concrete buildings, they can be off by 50 metres or more, and the phone reports how uncertain it is. A fair location check allows for this: it uses a generous radius, accounts for the reported accuracy and treats very imprecise readings as “unclear” rather than “outside”.
Flag or block?
- Flag records everyone and marks off-site check-ins on the attendance sheet for review. Nobody genuine is turned away by a bad GPS reading. Start here.
- Block refuses check-ins from outside the radius and from people who decline to share location. Use it once you know your venue gives reliable readings.
Setting the venue
The easiest way is to stand in the room and use your own phone’s location. For events that move between venues, set the location per session from the room on the day.
What location checks cannot do
A determined person can fake a phone’s location with special apps, and a location check says nothing about whether the person checking in is the person registered. That is why geofencing works best alongside a rotating code, one phone per person and, where the stakes are high, a selfie. Six ways to prevent proxy attendance.
Choosing the radius
A radius of 100 to 200 metres suits most buildings. Use a larger radius for campuses, parks and conference centres with several halls. If genuine participants are regularly flagged, increase the radius before switching to block mode, and check whether those check-ins came from a basement or a room with thick walls.
Reviewing flagged check-ins
A single off-site check-in 300 metres away during a session in a large building is rarely a concern. Look instead for people flagged off-site at several sessions, check-ins many kilometres away, or a group of flagged check-ins arriving at the same moment, which suggests a shared photo of the code.
Geofencing vs Wi-Fi and Bluetooth checks
Some systems check that the phone is on the venue Wi-Fi or near a Bluetooth beacon. These can be more precise indoors but need setup at every venue and often an app. Location check works anywhere a phone can find its position, with nothing to install, which suits trainings and events that move between venues.
Privacy
Tell participants that the session checks location and why. Ask for location only at check-in, not continuously, and keep only the result. Mention it in your privacy policy. Collecting attendance data responsibly.
QRtimer includes location check on every plan. See all features.