The unhelpful behavior is too many people coming out to try to see the zebra which scare it into running away.
How other than closing the trail while they search could they realistically target that behavior? Put checkpoints at all the entrances and only let people in who could prove they had planned their outing before the zebra got loose? Require people to attend a lecture on not scaring the zebra and pass a test showing they understood before they can use the trail?
We all own nature.