Why does Liza's hair have a built-in sweatband?

Definitely looks like a badly installed lace-front wig.

For ALL the obvious reasons (easy prep, etc.), many people (especially artists/performers) have begun using lace-front wigs as almost everyday wear -- most notably Beyonce' Knowles and John Travolta. Add Miss Minnelli to the bunch now.



Here's one favorite one of the lace-fronts on Kristin, Idina and Joel in WICKED:



Strong-as-heck glue on Miss Knowles':

Though lace-front wigs were designed for films, stage and TV... many artists how found that they are unnoticeable in normal scenarios so they've begun using them. So much easier to wear a wig instead of having to deal with dying and straightening your hair, etc.

John Travolta was 'found out' during a TV appearance on the Oprah Winfrey Show promoting the film-version of HAIRPSRAY. He was photographed a few days earlier in the Bahamas sporting a tight buzz cut then showed-up on Oprah two days later with longer hair.

Everyone knows that Beyonce' Knowles' hair is a lace-front (in performance AND in her everyday form), so this isn't news.



John Travolta BEFORE:


John Travolta AFTER: