I think the issue here is that they never stated this prior to shipping them even if it does say so in the instructions, information like this should have be disclosed to the buyers with the item description imho. It is not just that issue though. The filters catch the gimbal mechanism, I have seen several instances when r/f or electrical interference has caused the gimbal to re-initialize in flight, this would then cause it to get caught and put additional stress on the motors. The gimbal is pretty fragile, I would not want to put any additional stress on it (the gimbal motors) by fitting the filters after power up. Why try to create problems for yourself when you don't need to