"My Mammy" which Liza was singing 3 years after Judy Garland's death; possibly folks at PBS thought a non-blackface heartfelt version of this song might offend. She didn't do it a la Al Jolson, except for going down on one knee. The knee effect wasn't by itself meant to offend either -- Jolson had a painful hangnail or toenail which he dealt with once on stage by going down on one knee, and it proved an effective and unique stage gesture. The concert was only about 50 minutes long, and Bob Fosse repeatedly cut to Gwen Verdon cheering enthusiastically in the audience. I especially love the "Ring Those Bells" and the "Cabaret" sequence. So PBS showed approx. 45 minute concert in a 90 minute slot. Glad they showed it, but they rather did it a disservice by chopping it up.