I'd guess that you'd say it's pretty high. They get a law passed forbidding beautiful young ladies from demanding more from fat, old ugly cigar-smoking men than handsome men. If you said zilch, go to the head of the class. Such a law would deny them their most effective means of competing with handsome men, namely offering a higher price. The same principle applies to any less-preferred person or good.
Most people prefer filet mignon to chuck steak.
If we made a law saying that chuck steak had to be sold for the same price as filet mignon, chuck steak wouldn't sell. It couldn't offset its perceived quality differences by offering a lower price. I do speaking engagements for which I am paid. In the interest of fairness, suppose a law is passed saying that people had to pay me the same as they paid Friedman, what do you think would happen to the probability of my being hired. That produces effects not dissimilar from any of the above examples.