[amluto]

There are doctors offices where you are supposed to present a confirmation or ID to a patient-facing barcode scanner at checkin. If you let it scan your code at the wrong time, at breaks the checkin flow. I can only assume that a mildly creative barcode could compromise all kinds of things.

[EvanAnderson]

I know there are instances of SQL injection out there in the wild that are barcode-accessible. I think there was a DefCon talk about it.