Revealing mistake: If you look closely at Billy Flynn in the musical number "All I Care About is Love", right at the end when he takes off the boxers, you can see that he is wearing underwear underneath them.
Suggested correction: Not only is this not clear whatsoever, since we can't see below his waist, but this is happening inside a musical number, not meant to be taken literally. It is just theatrical exaggeration for the performance.






