Don't treat wild animals like pets ...

Bison Tosses Girl near Old Faithful

A group of tourons (combines two common words) surrounded a bull bison. Some, apparently were petting the thing. At some point it gets annoyed and charges, tossing a nine year old high into the air. Fortunately, she was treated and released.

Anyone who tries to hold Yellowstone accountable for events of this sort should be summarily laughed at.

I saw several incidents when I was there that could have ended the same way or worse...people walking their kids up to bison and elk and moose like it was some kind of petting zoo.