The kid that sits immediately next to my second grade kiddo - as in, like, 2 feet away - caught COVID. Did we hear a peep from the school? Nope. Because the kids are wearing masks, virtually nothing is considered an "exposure risk" any time anyone - staff or student - catches COVID, so everything carries on as usual.
The only way we found out is that our kid was facetiming with the kid who caught it and it came out while they were chatting.
So, we kept our kid out of school the next day, took the whole family to get the PCR test and, thankfully, they were all negative.
But, warning to all the parents in schools/districts where kids are wearning masks - they all very likely may have the same view of exposure risks...