Faith, Professor Stephen Bainbridge has some good comments along the same lines.

I think these cases raise a very interesting and difficult moral issue. Back in the early days of the Civil War, a wealthy individual who was drafted could pay a substitute to go in his place. Indeed, sufficiently wealthy individuals could buy their way out of the draft by paying a $300 commutation fee. An analysis of the 1863 draft in Wisconsin found that "Of the 14,955 men drafted state-wide, 628 actually served, 252 hired substitutes, 6,285 were discharged for physical reasons, 5,081 paid the $300 commutation fee, and 2,689 never reported." In other words, over a third of those drafted bought their way out of service.

In reply one of Bainbridge's readers nails it:

A two-tiered system of punishment, in which wealthier people are punished less, is something like the beginnings of the state maintaining two justice systems for different groups of citizens.

Punishment is more than time served. The sentence includes the conditions under which the time will be served. If you want to further undermine confidence in our criminal justice system, encourage the development of a "two-tiered system." And don't even get me started on whom the "good people" in "Bad things happen to good people," are supposed to be.