What is the test for appealing against a finding that a defendant's ability to pay a restitution fine was improperly assessed?

"[A] reviewing court ordinarily will not consider a challenge to a ruling if an objection could have been but was not made in the trial court." (In re S.B. (2004) 32 Cal.4th 1287, 1293.) "As a matter of fairness to the trial court, a defendant should not be permitted to assert for the first time on appeal a procedural defect in imposition of a restitution fine, i.e., the trial court's alleged failure to consider defendant's ability to pay the fine." (People v. Gibson (1994) 27 Cal.App.4th 1466, 1468.) Failure to raise the issue in the trial court constitutes a forfeiture of the right to complain on appeal. (Id. at p. 1469.)

The minor contends his claim is not forfeited, because the fines imposed amounted to an unauthorized sentence. An unauthorized sentence may be corrected on appeal despite a failure to raise the issue below. (People v. Smith (2001) 24 Cal.4th 849, 853.)

However, the unauthorized sentence exception to the requirement that a claim must first be raised below is a narrow one. (People v. Scott (1994) 9 Cal.4th 331, 354.) A sentence will be considered unauthorized only where "it could not lawfully be imposed under any circumstance in the particular case." (Ibid.)