When we first towing a TT in the US, we were told adding under-insured motorist protection (aka "UMP" in BC) to our policy was basically a must because of the number of under-insured drivers on the roads.
DW once got hit in a grocery store parking lot. She got out and casually started to take photos with her phone. The guy went ape-sh**t. Turned out he had stolen plates on his car. The cops and our gov't insurance co. were able to track him down so we didn't have to pay the deductible. Luckily he didn't get violent. Moral of story - ask the other driver if it's okay to take photos first. :R
Having to deal with a motor vehicle insurance company has to be one of the hardest things you'll ever have to deal with in life.