For the same reason that police can't ethically solicit sex from someone they've pulled over for a traffic violation: There's a power imbalance that unfairly bi

For the same reason that police can't ethically solicit sex from someone they've pulled over for a traffic violation: There's a power imbalance that unfairly biases the propositioner over the victim. Even if the boss asks politely, the subordinate knows that their job -- and likely their financial stability -- ultimately depends on making the boss happy...