Physical plant surveys need to become annual events. Inspection of piping added, altered, or extended during the year is highly recommended. Air gap arrangements must be visually inspected just as the certified technician must perform a ritual test on mechanical devices outfitted with test cocks. The intent and purpose of backflow prevention equipment are spelled out by law. Should an incident occur due to backflow causing property damage, personal injury, or death, expect someone to demand compensation.
Awards can be swift and substantial.
The best defense is avoidance of the problem, being prepared to prove your professional understanding of the law via impeccable record keeping. Professionalism is being willing to provide reasonable care. You can write directly to them to request information on their standards. Request Manual M-14, latest edition.