I suspect everyone makes the risk management decisions they're comfortable with. I generally ride in the middle of lanes, but there's usually no cars. When a car approaches I get as far right as comfortable, which is generally the right tire tread path. Gives me some right side runout room to accommodate idiots, encourages prompt safe passing. Some people will pass close, some will pass on blind curves, some will pass into obvious oncoming traffic driving the oncoming car into the ditch and me off the road (this has happened). I can't control them, just be ready! And having 4" of road to my right isn't being ready! But I don't necessarily need to clearly "take" the lane to control it.