Can't say I disagree with the firefighters, but I think there has to be a better option.
If the $75 is paid, the fire is dealt with as expected.
If the $75 is not paid, the fire is dealt with as expected, and a bill for services rendered is then issued. This bill should be in great excess of the costs associated with fighting fires. So if there are 5 paid FFs (at $20 bucks and hour), 3 hours of firefighting, and equipment etc., the bill should be in excess of $500.
So then, your choice winds up being... pay $75 yearly, or pay per incident. Your choice.
It's a win for the fire dept so long as they bill appropriately for services rendered to unsubscribed customers. It's simply a matter of collecting, which I would assume could be problematic.
On the other hand, then that makes the FD look bad as they'll be going after money from a family that just experienced some loss.
I dunno, they're sending a clear message. It's probably the most straight forward clear message to send for this case. Pay the annual $75, or risk watching it all burn.