I'm amazed at how much this happens every year, somewhere. People are beyond oblivious. I know for a fact that communities go out of their way to make it known "hey, we're in a drought...no burning of anything and certainly no fireworks!", and yet someone will always ignore that and do it anyway.
And this is what happens.
And I agree on them/their families, to some degree, being on the hook financially. And while they're probably too stupid/useless to assist in actual firefighting efforts, they can fetch water or supplies, or, at the very least, do cleanup work. Some sort of firefighting-related community service is totally reasonable in this case.
Because you're right...they are old enough to know better. 15 and 16? Yeah, that's definitely old enough. If it were a couple of brain-damaged three-year-olds, okay. But that's not the case. They do need to see, first-hand, what their actions caused.
This is not wrist-slapping time.
Those nitwits who started that huge fire in Gatlinburg, TN a few years back...they were tossing lit matches on the ground (hey, what's the worst that could happen?) and 14 people were killed (not to mention all the land and property that burned). Charges against the two twats were dismissed/dropped.
I don't even know how that happens unless there was backroom wheeling-and-dealing and knob-gobbling taking place amongst the two sides (prosecution and defense, along with the judge, the families of the two perps, etc.). Were the perps from the "right families" and some "they're good boys, let's not pursue this too hard" calls were made? Because I sure as shit couldn't go burn down half a mountain (and kill 14 people in the process) and be allowed to walk.