Yeah, since a ghost mouse do repeated actions with same coordinates not even a pixel different. So hence can be easily detected. Jagex can monitor and save logs off your mouse, and they'll find all your mouse moves exactly at that pixel and so it is most probably a bot...
Ive been baby sitting and doing it since 88 mage and i'm now 95. Haven't seen anything yet. I talk a lot to and change the off set every 500 casts or so.