Thanks for the feedback about the border crossings.
I've just learned of something called "Canada Non-Resident Inter-Province Motor Vehicle Liability Insurance Card" (the Yellow Card).
I tend to think it's probably not necessary because State Farm and AAA are well known enough that just the regular proof of insurance I keep in the vehicles should suffice. Having said that, I might just ask for one to have with me.
From the Metro Vancouver Convention and Visitors Bureau: https://www.destinationvancouver.com...ols/insurance/
All United States motorists are advised to obtain a Canadian Non-Resident Interprovince Motor Vehicle Liability Insurance Card. This card is available only in the United States through US insurance agents. All provinces in Canada require that visiting motorists produce evidence of financial responsibility should they be involved in an accident.
Another source: https://www.ccir-ccrra.org/PrivatePassengerAutomobiles
The Canada Non-Resident Inter-Province Motor Vehicle Liability Insurance Power of Attorney and Undertaking (PAU) was established in 1964. Generally, this document is filed by insurers in the United States who issue motor vehicle liability policies outside of Canada.
An insurer that files a PAU protects its insureds who drive their private passenger vehicles in Canada. Companies which have filed a PAU can issue a Canadian Non-resident Inter-provincial Motor Vehicle Liability Card (commonly known as a "yellow card" or "Canadian ID Card") to their insureds for driving into Canada. These insurance cards are used as evidence of insurance coverage if stopped by enforcement officials or involved in an accident in Canada. In addition, signatories to the PAU agree to certain conditions if an insured is involved in a motor vehicle accident in Canada. For example, the company agrees to meet the minimum third party liability limits required in the province or territory where the accident took place. (In most Canadian jurisdictions, the compulsory third party liability limit is C$200,000.)