Honeywell systems are so easy to program by keypad that most of my DIY customers opt to do it that way. Napco, on the other hand, is much easier done by PC. Also, the Napco PCI-MINI computer interface is inexpensive ($21 retail) so most of our Napco Gemini systems are programmed by PC. I usually walk the client through the programming process. It takes an average of 20 minutes to program a Napco Gemini P9600 and a little less for a P3200. The smaller panels are even quicker.
Since the vast majority of DIYers don't want CS monitoring, there's almost no chance of one of them causing the kind of problem this "professional" installer did.