I am not a native English speaker, but, in my understanding, penal law and criminal law are both the same thing.
For all practical purposes, this is accurate, at least in the United States. In regards to income tax, I think the moral obligation would only extend to what is actually income. The State does, of course, consider that one's income includes anything of any value that one might receive for any reason. I think this can be legitimately and morally questioned. The State might punish a person for having a different opinion on the matter, but I don't think that would, in itself, be sinful if one acted upon a different opinion.
For the life of me, I do not understand how a "tip" to a waitress or other servant can be considered income--which is why I always give tips in cash personally to the individual and not part of a docuмented bill. If the person I give such money to opts to claim it as income, that is his or her decision.