I find that a lot of the headphone MUP riders don't even check over their left shoulder before moving around walkers.
Even the headphone wearing runners are guilty of that.
I view headphone use on roads as Darwinism in action.
So, No, I personally save the music for on the Trainer, then I crank it.
Plus in California I think you'll find it is illegal to operate a vehicle including a bicycle using headphones in both ears.
Remember in the land-o-many laws
California....... If its not illegal, its probably mandatory !
Barry