"The Gemara explained that the punishments for giving false measures are greater than those for having relations with forbidden relatives because for forbidden relatives, repentance is possible (as long as there have not been children), but with false measure, repentance is impossible (as one cannot remedy the sin of robbery by mere repentance; the return of the things robbed must precede it, and in the case of false measures, it is practically impossible to find out all the members of the public who have been defrauded).