The USFS has a very stringent Safety and Operations policy. Everyone has the same book, the book clearly lays out procedures, responsibilities and authorities, uses a risk matrix, and safety is priority number one with fire fighting being secondary to that. They do not worry about expense being added to the cost of their doing business. The pilot has the last word after everyone else has signed off on the flight....but usually is involved in the initial planning. That gives him two chances to say no and plenty of oversight to prevent him being put into a bad situation.
That certainly isn't the case with EMS flying as it stands now.