With that being said, I think that anyone who tries to do anything to game the system to make it so they pay less in child support is scum. Money from child support is used for the benefit of your child. If you do not pay then you are not supporting your child and your child is suffering. Period.
Spoken like someone who has ZERO knowledge of how the family courts are operated.
This is the way it is supposed to be, but frequently one parent pays for all the expenses for the child and is still charged child support (just based on the disparity of income levels). Often times that other parent just spends all the money on themselves.
The spending habits don't matter when it comes down to court. All that matters is the percentage of physical custody vs. the disparity of income (at least in California). As long as one of the parents is not doing anything illegal with the money, or endangering their child, they could be making a Range Rover payment while their child wore the same pair of clothes to school every day, and it would be almost impossible to change it.
Believe it or not there is an ongoing case right now where a male student (who was 14 I believe at the time), had sex with his female teacher who was an adult obviously. This constitutes statutory rape, which is a crime. The two went their separate ways... About 2 years ago, he received court paperwork in the mail stating that he owed over 15k in back child support. Turns out that he got her pregnant, the woman kept the baby, and despite this child being the offspring from a crime, the state still froze his bank accounts and started garnishing his paychecks. This child is now 5 or 6 I believe.
If the teacher in your example is suing for back child support then she would essentially need to admit to statutory rape in open court. If she were to admit this then she should be prosecuted and would likely be sent to jail, and have the child taken away from her so child support should not apply.