And yet, any agreement that is going to be approved by the court is not going to be "rubber-stamped" - it has to conform to the rules.
That website said very clearly that those aren't "rules", they're guidelines.
Provinces, including the one I am in, have exercised their right to add additional conditions.
Firstly, this is not what you originally claimed. You claimed that a court will intervene in a civil agreement between parents of a child concerning maintenance. This they will not do; they've more than made it clear in the website you linked to!
Secondly, while a judge can modify an order before the court, it's meaningless if both parties are opposed. Courts have never, in my experience in court and out of court, forced two parties in a civil matter to agree to terms when they already have agreement in a different set of terms that violates no law.
Thirdly, and this varies from jurisdiction to jurisdiction, judges routinely rubberstamp amicable agreements. They can get into serious trouble if they don't (there's a whole lotta laws around this one).
Fourthly, (and this also varies a lot) income from maintenance payments are not taxed - they have already been taxed when the paying parent received it, and as they are not tax-deductible on their way out, they are not tax-attracting on their way in to the receiver parent. When you use part of your income to provide income to an employee, you pay no tax on what you pay the employee (they pay their own taxes). As far as I am aware, this legislation went into effect in Canada on May 1, 1997.
Go before a judge with a child support agreement,
I've done so, and do so routinely.
expect it to be scrutinized. It's public policy here nowadays.
It is scrutinized. Unfortunately the court cannot intervene in a civil matter unless one or both of the parties ask the court to do so. So they scrutinise the document, look me in the eye and ask "Is the plaintiff/respondent fully aware of the implications" and I say "Yes, m'lud". The court can use its discretion to refuse to approve the agreement as a judgement, but luckily in Canada and other places a judgement is not needed for maintenance, only a written agreement.
Judges will automatically suspect that any amount less than the guidelines is being used to dodge taxes in return for getting a smaller payment "under the table."
See above ...
On top of that, things like getting an order to garnish wages, seizing income tax refunds, don't even require a subsequent court hearing - just go to the Percepteur des pensions alimentare with the agreement, and the seizure goes through automatically. No hearing or other proof required. To get it lifted, the person has to go to court and prove the seizure is in error.
Sounds like a real hellhole - seizure of assets without proof of debt. Luckily it isn't true for Canada (Seriously, who have you been talking to? Maybe you should engage a lawyer at some point to get some of your misconceptions corrected?).
They can also suspend your driver's license, passport, and other permits.
The link above says that the evidence and claim of non-payment is from an enforcement agency not the receiving parent. So, no - the woman cannot simply go and get all assets seized automatically with nothing more than a signed agreement and her word.