A scan is a check, not a guarantee
Barcodes can reduce manual entry, but a readable label can still identify the wrong product if the product master is incorrect. Duplicate codes, pack-size confusion and damaged labels should be resolved before changing the picking process. No fixed error-reduction percentage applies to every warehouse.
Design the confirmation
Decide what the operator must verify: product, location, quantity and possibly batch or serial details. Scan one unit and then a carton in your test. Confirm how the system handles a wrong item, an unknown code and a quantity that exceeds the order. A beep alone is not proof that the intended validation happened.
Use your real devices
Try the scanner, browser, label stock and network in the actual working area. Test a long shift, gloves where relevant and an unavailable connection. Camera scanning, offline work and specialist label formats require explicit confirmation; they are not interchangeable with a keyboard-style scanner.
Measure a small pilot
Record checked order lines, incorrect lines, corrections and time spent resolving exceptions before and during the trial. Keep the definition and order mix comparable. Use the results to decide training and hardware scope, rather than relying on a vendor's headline percentage.