go scot-free, to

To escape from some predicament, accusation, or wrongdoing without incurring any penalty or punishment; to be acquitted of all charges for some crime or crimes. It sickens me that all these bankers that ruined our economy get to go scot-free, while millions of people have suffered as a result. Due to an error in the filing of evidence by police, the suspect ending up going scot-free.

to go unpunished; to be acquitted of a crime. (This scot is an old word meaning "tax" or "tax burden.") The thief went scot-free. Jane cheated on the test and got caught, but she got off scot-free.

To be let off without penalty or punishment. This expression has nothing to do with Scotland, but rather with the early meaning of scot, that is, a tax assessment. Thus scot-free meant not having to make such a payment, and later was extended to mean being exempted from other kinds of obligation, including punishment. The earliest use of the term dates from the Magna Carta of 1215. Later it was transferred to nonlegal issues, as in Samuel Richardson’s novel Pamela (1740): “She should not, for all the trouble she has cost you, go away scot-free.”