The point of the tests is to evaluate the schools overall effectiveness. As much as test-centric cramming effects those results, it creates a false picture.
Some notes and observations:
Because the state both accommodates and encourages this scenario, the fault can't reasonably be laid on the schools.
A more impeccable (but problematic) way to handle these tests would be for the state to show up with little/no notice and administer it.
I'm personally inclined to scrap state assessment testing altogether. The zero-sum nature of pitting the schools against each other for limited funding consumes a great deal of precious teaching time for little clear benefit.
This conversation happened at our county's first charter school. A few years earlier, this principal happened to be my son's PS teacher.