That doesn't seem foolproof to me...they shouldn't need to care which TX is plugged into the floor box. Give them one button on the UI that says Floor Box or Laptop or whatever is appropriate, then use the logic like in the screenshot below so that when they push the Floor Box button, it routes the correct floor box. At some point the labels will fall off, someone will press the input 4 button when the input 1 TX is connected, or something like that.