Absolutely right.

A ruling that a poor person shall be forced to spend money on a fine rather than food or lodging should not be considered 'cruel and unusual.'  If it was, then it would be a Charter violation: 
"12. Everyone has the right not to be subjected to any cruel and unusual treatment or punishment." Fine 'em all enough that they cannot afford lawyers who would burden tax payers with a Charter defense.

Maybe the children of such a defendant have a case based on the cruel and unusual defense, but then they would simply just be taken by the State. "He can't care for his kids, your honor, I recommend that they become chattel of the State."