We think its a good idea for the power lights and had them fitted before series 7 along with weapon active LEDs and disagree with John. Ive seen robots with the link removed that have still been active due to wiring incorrect and if power lights across each speed controller light up then this can be spotted sooner.

One possible example of this is if you use a speed controller with large capacitors in it there is suffeceint power in them to activate a weapon relay long after the link is removed and the lights would show this.