I'd interpret the "minus first N per year" to mean that you get a few "free" fires per year - but after that your habits filling your closets with oily rags, overloading electrical extension cords, and smoking in bed will start to cost you.

Fire is one of those things that really sucks for you - but also really sucks for your neighbors.

You never want to supply any reason for someone to demur about reporting a fire.

I'm sure someone somewhere will interpret it a 3 free demos of firefighters at home for their kid, with sirens and light, pretty entertaining (It's a reference to the Freakonomics study that, if you make parents pay by the minutes for being late getting their kid, they basically take the fine as a slightly expensive childcare facility).