This is an old story.
About a year ago, I had someone who smash through my car's right side-mirror. I called up NRMA and asked about their policy "if it's not your fault we won't charge you excess" which they were heavily promoting at the time, they informed me that I would lose my no-claim bonus for next year.
Which just means I'll pay the money later when I renew the insurance.
I ended up calling off the claim and just replaced my mirror from a second-hand parts store.
Mirrors aren't that expensive to replace, but I've had this insurance for 10 years and each year it's cost me about 10% of the cost of the car, if I totaled it. In hindsight I don't think I needed car insurance at all.