B2L2

"Hit and run" need a witness???  It shouldn't be called as hit-and-run then.  LOL

For accident with multiple cars in a chain, the first question they will ask (for cars in the front) is whether you feel a single hit or multiple hit.  You could probably guess out why they ask this question?  It isn't always true that all 4 cars at the back is at fault.  It really is case by case.  Of course, it is still good to leave enough room between cars around you.

B2L2

I had a highway accident 1.5 months ago involves 3 cars in total.  How more recent you mean?

For the one being the front car, you got hit 2 hits/push, the 2nd car behind you hit your first and then followed by the 3rd car.  So the 2nd car is in fault or at least partially in fault.  If you got one push, it means the 3rd car pushed the 2nd car during the accident, and 2nd car in this case isn't in fault.

In my accident, no witness involved.  3rd car paid for all others.

I totally agree that ICBC does the trick to blame all parties, and it is always like that.  When case in doubt, ICBC they simply do 50-50% trick.  Both parties get increase in their premium in 50-50 case and ICBC gains the most out of it.

B2L2

That's exactly what I like to point out that it is still case-by-case.  Being a middle car doesn't go into fault by default.  The best is not to get into any accident.  ICBC is very tricky to deal with.

Back to OP's case, I think you definitely should talk to ICBC and see whether the comprehensive insurance cover your car under vandalization.