I'm kind curious, did Canada have the same spike in the "knockout game" that the US did?

If it did, that would point to a US and Canada crime trend correlation. If not, then you can't just say that the one static variable, city/county level policy and the independent variable, immobilizers, are the only factors.

You have different criminal populations, societal values, amounts of government aid, rehabilitation programs, etc that all play into the analysis.