Yup, remember, the hood and plastic panels all around the car have been designed and tested with pedestrian impact in mind. Put a chrome "push bar" on the front, and a pedestrian that could have walked away with a bruise may end up in the hospital with fractured kneecaps. The insurance could say you altered the safety characteristics, and contributed to the difference in injury. Laws are stupid sometimes, but... if you were hit by someone with a soft bumper but decorative spikes in the front, would you be content with "that's ok, it'll heal" or would you want your medical bills paid?