There are many bars that charge only guys a cover charge. I don't see how this isn't sexual discrimination. Is this legal? I've heard that it has been outlawed in some jurisdictions within the US.
Of course it's sexual discrimination. There are even bars that charge women half price or, in some cases, free drinks. Guess why?
But, its legal. Most women wouldn't be caught dead in a typical bar unless they had some incentive to enter. Men will never complain because they want their prospective hook-ups to be as intoxicated as they are.