Do string players read NNS in Nashville?
I remember a Diva requesting a key change two hours before taping and being advised the 20 or so orchestral players had a fixed score.
I don't know about string players, but living in Nashville, I can tell you that every musician I know of knows the NNS. And if someone changes the key, they just go with it. It's never a big deal.
Now, if you have a music in standard notation in a specific key you may be in a pickle unless you can transpose on the fly. But there are so many musicians in Nashville who can just play...anything...without a chart. My brother can do that. He'll either ask for the chord progression, or have someone play a few bars of the various parts...and he's off to the races and doesn't miss a beat. It dumbfounds me how that can happen.