PENKO..
That's why I try to make it a habit in the climb to switch both needles OFF, so that during the approach preparation I have to make a conscious effort to re-select the correct boxes. It's a small silly personal rule, but as I said, it's an easy mistake to make in an automated flightdeck where all the tuning is done via the MCDU.
With the switches OFF how do you monitor flight progress? I was taught, and teach, the use of raw data as a backup throughout the flight, which in most parts of the world means VOR only in the cruise. If you develop awareness of the tuned aids - you will have better awareness of the switch positions required at various stages of the approach, and you won't make those easy mistakes.. or if you do you will spot them.