I think the best way for me to explain govt thinking is this first hand experience.

I had a friend of mine with a '98 Cadillac back into my later model PT Cruiser, back bumper to back bumper.

There was not a bit of damage to my back bumper but it punched a dent & hole into his. I asked him what he found behind the damaged bumper cover and he said nothing, no foam or anything. I know for a fact that my PT has reinforced foam in behind the bumper skin and that was the reason for no damage.

His estimate to replace the bumper on the Cadillac was $1,300 for a collision that probably was less than 5km per hour.

BTW, I'm not here to defend Chrysler or big corporations but to explain why your Cdn. govt has stricker bumper regulations.