Actually, that's not what I said. In the post that you are referring to, I wrote "...a frame of reference can be built around this question..." Nowhere did I say that the questions themselves constitute valid reasons to act. Anticipating your follow-up, examples of valid reasons to act could include being witness to, or involved in, one or more incidents in which an individual engaged in careless, reckless, negligent, or non-compliant behavior that jeopardized the safety of others. Whether one such an incident, by itself, would be sufficient grounds to confront or report the individual depends on the circumstances, and the willingness of those involved to act. In all cases, whether to act and what action to take are decisions that must be made by the individual--as EdFred wittily noted, there's no ACS to turn to for guidance.