I was asked for this info and i couldnt remember it in detail so i searched it out, this info is from The Cabals Secret Hideout, thanks to Traitor.
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Evil Rob/Steal Settings
The Math:
There are two settings that affect how much you can rob or steal. The RobFactor, and the StealFactor. These settings are determined by the Sysop. (Although in MBBS mode, they are fixed.) They are measured as a percentage, i.e. 50%.

Here is the formula you need to use to figure out how much you can rob from a port with minimal chance of a bust.
(3 / %RobFactor) * EXP
Example: (Rob Factor is 50%. Your experience is 10,000.)
3 / .5 = 6, 6 * 10,000 = 60,000
You can rob 60,000 credits.

Here is the formula for stealing holds:
EXP / (30 * %StealFactor)
Example: (StealFactor is 70%. Your experience is 3,500.)
30 * .7 = 21, 3500 / 21 = 166.6 holds. (166 holds, drop fractions!)

For your convince, I have put the default values for a MBBS and a Classic game.
MBBS:
EXP * 6 = Maximum Credits you can rob at once.
EXP / 21 = Maximum holds you can steal at once.

Classic:
EXP * 3 = Maximum Credits you can rob at once.
EXP / 30 = Maximum holds you can steal at once.

Be sure to check the settings the sysop is using in a classic game by pressing * at the Game Menu. (The first menu after you choose which game you want to play.) And remember, even if you follow these settings, your chance of busting is around 1 in 50. You WILL bust!