In the Candlestick scene, when "Johnny" leaves his seat (and is then kidnapped) there is no one on the field and no one in the stands in the background. When we see the parking lot in the next scene, there are no cars anywhere.
Notice that when Brenda Vaccaro approaches the bad guy's limo at the Palace of Fine Arts, the rear window is open. Switch to Michael Douglas watching from his car. When Brenda arrives, the rear window is up.
Keller: California, born and bred—I'm from Modesto
Sydney: I didn't know anyone was from Modesto!
Keller: Hey, my dad used to say Modesto is a good place to be from. So I moved myself to Berkeley.
Guest Brenda Vacarro was married to star Michael Douglas.
Filming Locations: Opening part of Act I was filmed at Candlestick Park during a Giants/ New York Mets game; the finale of Act IV was filmed at the Palace of Fine Arts.