From: aran armath
Depends on several things.
1 are you power chopping?
2 what script you are using?
3 does the player look like the rest of the legit players?
4 lvl 20+ combat?
5 Luck
Those are great factors to take into consideration.
By the way, it is not really reccommended to auto on just one account. I have done it before for seven hours mining and banking but I sat by the computer and was studying so if a random came up I could pause the script solve it and start back up.
It's to risky to just auto on one character. The movement path and accuracy will catch players eyes if they see a person on doing the same thing for a few hours.