We advise not using QR codes for the simple reason that they can be easily copied and then scanned from anywhere. NFC tags ensure that your staff have had to visit the tag locations each time to tap them. This is more of a fail safe option and ensures you are covered for any incidents leading back to checks being done. QR codes also require using paper and we are trying to keep Dunatis as eco-friendly as possible.
For peace of mind we also capture data on the GPS location of the device when the check is done.