I fly in open only with small ships which re-buy value I can make back with one trade run with Python. Only way I would play fully in open with big ships would be to make the monetary loss of ship and cargo due to fellow CMDR much lower. If I can make back my lost credits with one trading run, I am good to go.
I do not mind if someone blows my ship, but I hate the lost time and effort it makes me to re-buy the ship and cargo lost. Cutter's re-buy is so high I would never want to fly it in open.
I fly in open in small, fast ships, or even my sidewinder for a laugh .. minimum rebuy costs. My bigger ships Corvette and Cutters where rebuy costs are 40+ million, I do not do