This. Both my bands (one is gigging for the first time in a fortnight, the other has gigged a couple of times) have flexible approaches.
The guitarist in the blues band could have huge semaphore flags on his back, he's that good at telegraphing the changes.
The covers band want the vocalist to adapt to the audience reaction, so we've agreed a combination of hand signals and vocal cues.
What is out of order is just randomly changing without signals or consideration.
If it goes fubar now, you won't be gigging before 2025, unless the band decide to get serious.