Nora Clavicle and the Ladies' Crime Club - S3-E19
Revealing mistake: Not only does Batman's solo flute play two music tracks at once, it also keeps on playing after he's taken it out of his mouth. (00:20:00)
Nora Clavicle and the Ladies' Crime Club - S3-E19
Visible crew/equipment: When Batman and Robin are seated in the Batmobile with Batgirl standing alongside, while they listen to the ridiculous police dispatcher, the reflection of the moving boom mic is visible on the front windshield's chrome trim. (00:10:00)
Nora Clavicle and the Ladies' Crime Club - S3-E19
Revealing mistake: When Robin calls Chief Linseed to get her to mobilize the entire force, Linseed and the others are useless, and in the two closeups of the mice scurrying on the rug in front of the desk, a few stunt wires are visible. (00:18:50)
Nora Clavicle and the Ladies' Crime Club - S3-E19
Revealing mistake: When the crime fighting Trio are playing the tune on their toy flutes and reach the docks, in the wide shot the stunt apparatus (a bar) is visible, and in the closeups of the mice procession their wires are visible as well. (00:20:50)
Answer: There wasn't one singular city used. It was shot in and around various locations in California, plus on a lot of sets and backlots. Ex. Some scenes were shot in LA, some in Pasadena, some in Santa Barbara, etc.
TedStixon