Well I would not be so negative. I realise now that the issue is not burning down a forest. There must be a build that is fire proof. Has to be. Just needs work and time and more expense.
Flaming debris and leaves could be dealt with by sand in the box. You can even test it burning and make a cool video - though not sure how to make it catch fire.
I will not give up my quest, it just means a lot more steps in the process. One day someone will manufacture such a ready-made node with all the safety certificates, 100% guaranteed. It would be sold as “Mestastic solar node for petrol refinery” or similar… lol.
And there are LiFePo4 batteries such as the Jackery Explorer 100 Plus, which are completely and utterly harmless regarding fire. I had a different 100 Ah LiFePo4 running in the house without any worries - and the existence of these batteries is what allowed me to step into DIY solar power without having to worry about the fire risk to my home. This is one reason I use them in my builds if I can.
The Jackery Explorer 100 Plus LiFePo4 battery is magnificent and runs a 0.1 mA node for about 9 days and the RAK 5 times longer than that. Unlike other batteries in Europe, it does not automatically switch off at the currents drawn by Meshtastic nodes. A really good piece of kit. BUT there is a problem with the USB C input from the solar panel which I thoight I might have solved but did not (no thanks to Jackery technical dept) (see section “Testing using USB C input via USB A output from panel to prevent drain of battery by the solar panel” in this post Solar 24/7 store & forward pole node using off-the-shelf components: test); and not sure it works for smaller non-Jackery panels, so it would have to be a “proper build” that is not a hidden construct.
I think the aim of making it cheap and safe is unlikely to be realised, but making it safe enough to sleep at night is possible.