You could postulate that they are the ones that can either afford it or can somehow justify the extra cost. For example, my wife can use a walk/bus/subway/subway/bus method to get to work. Or she can drive in 45 minutes of busy commuter traffic. She drives . . . We can both afford it & justify it. 
Ian
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'87 Carrera Cab
----- “Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.” A. Einstein -----
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