Every situation should be looked at, and every angle should be measured accurately. First off, coming forward and admitting your fault definitely shows a undeniable hint of integrity, whether it be out of fear of getting caught, or because you have the actual guilt, the fact that you're saving the staff's time instead of waiting for it to be dug up is a step in the right direction.
Let me break it down for you. User X is a serial ban evader/scammer, User Y has scammed in the past, but it was never habitual. Both were never caught, but decided to come forth.
User X, having had a long history of rinse & repeat scamming should definitely be punished accordingly, perhaps even denied a chance to return. User Y might be pardoned given that they are checked thoroughly, their story corroborates with the offense, and there are no other mishaps that might have been left out in their pardon. Now of course, even in that situation I can guarantee you'll have to work off a TwC and/or serve some ban time; But as far as giving User Y a second chance in the community - I don't oppose that at all.
Think of it like the legal system. You're tried for your crimes, sometimes you get off with probation, sometimes they send you to the pin (Internet without sythe), sometimes you get paroled out after you serve some time.
The matter of the fact is we're all human and we're all prone to make mistakes and whether or not you scam 10M on Sythe, or pocket some candy bars at the gas station; It doesn't make you any better or less than the next person. What matters is if you're truly remorseful and capable of making a change.
On another note, as someone who has had experience in the pardon system here on Sythe, I can definitely say that situations are looked at, they are weighed, and the staff has/continues to do a decent job regulating the system to be as fair as possible.