I have used the blue/green wire to signal relays on literally dozens of bikes, and seen well over a hundred done this way. Remember, "switched" power only. In the referenced thread the OP used the blue/green wire to actually power something, big difference. You use the B/G wire only for a switched voltage to a relay that actually turns on the power to an accessory.
Note that the trigger/signal wire goes to terminal 86. Power in to 30 and out to 87.