When scanning a barcode that isn't recognized, offer to create a manual entry with the barcode attached
As a fallback feature, I would like to scan any barcode/qr code/etc, and then go through the manual entry creation flow (select train/ferry/accomodation/event/restaurant, etc.).
This could alternatively or additionally also work the other way round: create an entry, then add any barcode by scanning it, similar to how you can add file attachments.