[luv2teach2017]

It's called a "letter of reasonable assurance.". The districts aren't trying to " reassure" you. It's actually a CYA legal measure to ward off EDD claims by establishing that you have an ongoing "assurance" of employment with that district following summer break (in other words, you remain on their active sub list and don't have to reapply).

That may work under normal circumstances, where you have established dates when schools close in early June and reopen in late August, for example. But these emergency closures happened unexpectedly and there's no way of knowing when the schools will reopen. There can be no "assurance" of employment, in other words.