> What if something goes wrong and all the children roast alive or something?
The real risk here seems to be "the HVAC stops working, the person who implemented it is indisposed/gone, and there is no entity to recover money from to get someone else to fix it"
Do you replace your working appliances and vehicles in your home in advance of their failure just in case? Or do you wait, and then spend the money for a repair? Perhaps you could have a backup system in a storage closet?
In the US, school taxes to a school are generally from the local neighbourhood and not the city at large, so advocating for spending to replace something that isn't broken might mean needing to take currently allocated funds from other programs if some contractor says they can only give you a new control system if you agree to let them replace all the boilers as well.
The real risk here seems to be "the HVAC stops working, the person who implemented it is indisposed/gone, and there is no entity to recover money from to get someone else to fix it"