That just punts to software in the device. That... could be better if it's contained to the device, but that's a big if, and even then the problem can still occur, it's just that you hope the damage is limited to needing to restart the device or so.
it usually is? you still need to do some manner of input validation on the decode. It helps when the barcodes you're reading have a known structure - then you can validate for the structure and its pretty easy.