Trope: Police have to keep bad guy talking on the phone long enough to trace them and find their location. Professional bad guys hang up right before it triangulates their coordinates.
Apparently, Hollywood’s been getting this inspiration from a pre-digital age when they use this trope in movies. See link for more info. It’s just funny that most of the “tracing the call” scenes I’ve seen are definitely after the 2000’s.
Another link: https://slate.com/news-and-politics/2002/10/how-hard-would-it-be-to-trace-the-sniper-s-phone-calls.html
A fun gif: https://i.gifer.com/9QtC.mp4
I make a point to say aloud “why didn’t you tell me how many people are before me in the queue or an estimated wait time” while the hold music is playing, in hopes someone will hear it and submit a feature request for me