Event organizers ask the same question before every large conference: will check-in hold up when a large crowd arrives in the same thirty-minute window. QR-based check-in answers that question well, but only when a few specific things are set up correctly ahead of time.
Why QR outperforms manual lists at scale
A QR code on a badge or a phone screen scans in well under a second on a basic tablet camera. There is no typing a name, no scrolling a spreadsheet, and no judgment call about whether one spelling matches another on the list. The code either matches a record or it does not.
That simplicity is what lets a single check-in lane process attendees continuously instead of in bursts. Add more lanes and the throughput scales close to linearly, which is not true of manual verification.
What actually slows QR check-in down
The failures we see on event day are rarely about the QR code itself. They are almost always about the surrounding setup: a scanner running on unreliable venue Wi-Fi with no offline fallback, a badge printed with the code too small or too glossy to scan under venue lighting, or a single check-in desk trying to serve an entire arrival wave.