Remain exempt from a law even if it changes?

Question

Let's say you won a case in Canada that made you exempt from Income tax as it was illegal. Later, the government decides to make an amendment that makes Income tax legal. Do you still remain exempt?

Answer 1

The Original law,in Criminal Cases is the rule.
But Financial Law and Taxation can be exempted from the rule and overide or ammend any pre-existing law.
You were Tax Exempt, but you are not Tax Exempted after a certain law is Enacted. That is how it works.
And bussiness is good.

Answer 2

What you are referring to is called "ex post facto" - after the fact. In your example, you would be protected against any action for the previous violation, but may be (the government has to prove their case) liable for any infraction in the future.

Answer 3

if your mexican your exempt