1. You'll be on Federal property, meaning the crime will be tried in Federal court.
2. By law, all of Yellowstone, including the Idaho portion, is governed by the US District Court for Wyoming.
3. The Sixth Amendment requires the jury for any Federal case to be drawn from the same "state and district" where the crime is committed.
4. No one lives in the Idaho portion of Yellowstone, therefore, no one lives in that "state and district."
5. Therefore, no jury, and therefore, no conviction."