There is another issue with a faulty brake light switch. There is a connection between the switch and the ECU, so that when you brake, the switch sends a signal to the ECU and it cuts power to the engine (which is why you can't heel and toe most VAG cars now). Therefore if the switch is sticking on you can find the car suddenly losing power, which is pretty unnerving. This happened to me on my Leon and I couldn't understand why the car was suddenly slowing down without any apparent reason. I have had four new switches on my SEATs, so a faulty switch is definitely a possibility.