indeed it varies, if you could get a mouse recorder (axife is a good one) or any that randomises your click it should be fine.
I was able to get 1-99 fletching in 2 weeks using an mouse recorder (on a lvl 3) this was like 3 years ago and still no ban.
I depends on what your using it for, and if there is also alot of people doing the same thing. Because if its something only you are doing, then i'd say its very unlikely to get you banned.