alt Hacker NewsNot comparable at all. The US is one market unless you have a compelling reason to protect your state market. Canada is 10 separate markets with provincial agreements between them - all protecting themselves. Easiest example is Quebec.
I.e. Opt in vs Opt out but more complicated.
The US is the opt-in system where the States regulate everything not specifically allocated to the federation and Canada is the opt-out system where the federal government regulates everything not specifically allocated to the provinces.
Of course it's more complicated -- the US's inter-state commerce clause has been broadly interpreted by the courts.