So... our school district did that for years. Universal screening in 3rd grade with a non verbal test (Ravens Matrices). And then stopped after rampant cheating on the test was exposed (a number of parents downloaded the test from the internet and prepped their kids). These days we are back to teachers and parents nominations, with the results you would expect.
Seems a bit heavy-handed of the district.
Given that most of the tests are only sold to, and administered by, licensed professionals, I'd think the school would be issuing some complaints to the professional licensing body to tip off any service providers (or trained parents in the student body) who might have enabled the cheating.
Professional sanctions would be a good natural consequence for cheating.
