Monarch authority

Over the weekend, I visited the Ellwood Main Monarch Grove and saw the many butterflies eating and flying and clinging to trees. One great spot to view butterflies was near the creek, where the monarchs drink whatever water is there. You can really see the butterflies close up there. However, that means kids can easily go catch them as well.
When I first passed the spot, I did find several kids running around with butterflies on their hands and disturbing their activities. So behind me, someone started yelling at the kids to get out of there and not chase the butterflies (I don’t know if that was in an official capacity or not).
After walking around the grove and returning to the spot, a new group of parents and kids had congregated to see many monarchs drinking the water. They had clearly been told to only watch, but you could see the kids getting closer and closer until they were picking them up by the wings. Unfortunately, the parents weren’t willing to tell their kids to leave the butterflies alone, attempting to tell the kids to let the butterflies land on them, as if kids had that kind of patience.
Eventually, the young kids left, leaving two separate, smaller groups: a family with older children and a few guys in their 20s. Each commented on how what the kids shouldn’t have been grabbing the butterflies, and one even talked about how the parents should have stepped in more. In my mind though, the question was, in the absence of the appropriate parental response, shouldn’t one of them or myself have stepped in, since they would probably have listened to an authoritative voice regardless of whether it wields true authority.
I believe, we didn’t feel right telling other people’s children how to behave. We felt we lacked the authority to tell anyone else what to do. In truth though, we had the moral authority. One that the parents of the children would clearly recognize. If one person would say it, others would support it.