> Insurance here is mandatory here for all motorists.

You do know that insurance being mandatory doesn't stop people from driving without insurance, right?

> If you are hit by an underinsured driver, the government steps in and additional underinsured motorist protection (e.g. hit by an out of province/country motorist) is available to all and not expensive.

Jolly good for you.

If I don't carry underinsured coverage, and someone totals my car or injures me with theirs, I'm basically fucked.

Even if you have uninsured coverage, you might still be dead.