I think TRAQ and risk assessment are good, but I just don't see how they would really hold up in court because they are very subjective. In a storm even a healthy tree can fail, so there is no way to prevent all failures unless you want to clear cut roadways and properties.
The idea is reducing risk. There are risks in every facet of life. TRAQ was designed to line up with the language and procedures used in the legal and insurance industries.
We recognize there is risk, but how much risk? There is certainly some subjectivity to it, but as a risk assessor, my job is to provide information that would stand up in court.
So on this tree, that might look like "Yes, the tree that failed had an identified defect. However, a cable was installed and inspected according to ANSI A300 Standards in order to mitigate that defect. Once that cable was in place, the likelihood of failure was reduced to improbable , making the tree in question a low risk tree despite the fact that we recognize a Frequent occupancy rate."
(Now, if the cable didn't meet ANSI standards, there is a lot more trouble there...)
Or for a tree that had been identified as "Improbable" failure with no visible defects, it might be:
*The weather event that caused this failure was an abnormal event.
*The defect that lead to failure was not detectable with a visual inspection and there was no indication that a more thorough inspection was warranted.