Mark,
There were many much closer than I. The rangers were warning them and trying most unsuccessfully to keep them back. Those two (idiots!) you see in the last photo, sent the adult moose rushing into the trees, and frightened the little one so much, that it went around the opposite side of the visitor centre to its mother. They eventually reunited at the back of the building.
BTW, they were individual photos I took, not shots from a video.
Lifey who respects that they are wild animals