We have flexibility on the resistor. We are using a 24V power supply to drive all of the lights/annunciators. Most of the annunciators have an integrated pushbutton switch and use a common voltage source for the light and switch. When the switch is not pressed, there is 0V, and when pressed the voltage source (usually 24vdc) is passed through the switch.
In our application we do not need the 24V coming from the switch as we are using the Arduino to read the switch and take action.
What do you suggest would be a better location for the resistor? Just for educational purposes, why is the current location "odd"?