Comment Re:As much good as I think these things can do (Score 1) 131
If one wanted, one could design a scanner whose only data-output path was an audible tone. You could download a list of license numbers into it (using a unidirectional data transfer, e.g. via a serial port with the device's TX pin removed), and then it would beep if it saw one of the plates in the list, and that's all it would do.
To hack it to output a list of license plates it had scanned that day would both require hardware and software modifications -- not impossible, but inconvenient enough that it's unlikely most police departments would be capable of doing it.