Maybe I'm not fully understanding:
- OP is NB climbing a grade with a single NB lane.
- Class A is SB (in the center lane?)
- Minivan is SB and is passing in the NB lane.
Was there someone in the SB right lane forcing SB traffic to run 3 wide?
How steep was the grade and in which direction?
Were there other SB vehicles in close proximity?
Quite possible, the Class A wasn't expecting or watching for a crazy to cross the double yellow. If there was another RV behind, was the Class A worried that RV behind couldn't stop?
With hindsight it may have been better if the Class A hit the brakes but when being passed, the appropriate response is to hold a steady speed. If the Class A had hit the brakes and at the same time the minivan decided he didn't have enough room to pass and hit his brakes, the minivan could have been trapped in the oncoming lane. By holding a steady speed, you allow the passing vehicle to react without having to worry about what you are going to do.
If I'm understanding the situation, the blame is squarely on the minivan. No need to drag others in.
