

I don’t think something of this risk should be left to individual, non-publicly maintained or controlled devices. This is specifically an area where the time to act is short and oftentimes the public is either in the river or river adjacent so they wouldn’t have their phone.
That said, there should be better cell service for the reasons you listed, I just don’t think it is the solution to the loss of life here.
They are not open source but I just started dipping my toes into the Mikrotik ecosystem and the hardware has been pretty nice from what I have seen. I am not a network guy, just a homegamer coming from normal asus routers though. They have a couple of options for adding cell service via sim cards but I have not looked too far into it.
Edit: it looks like there is an openwrt release for the rb5009ug I am using. I may need to check that out.