How accurate are bar code scanners?

We sold some badge scanners to one of our customers who later said he was getting incorrect data from his scanners. We got a sample badge from them, scanned it, printed it, and attached it to a label rewinder. We then took the badge scanner apart and mounted the scan module near the label and recorded each scan into Excel:

We were able to collect over a million characters in just over a day. The result? Zero errors. We looked elsewhere for the customer’s issue.