How is that gonna work? You can't just sniff the traffic between Google and the students(SSL & stuff), and I very much doubt that Google itself will let you take a look in their datacenter.
My point is the insinuation that Google or other tech-ed companies are inappropritely classified as "school officials" which the allows them access to data to profit from is made. It's all speculative what-if without any substantive reporting. No where in the article is a comment "Google declined our requests for information" or "Google declined to comment". The closest thing is a general quote from an EPIC associate about tech-ed companies being hush about how they use their data.
Fortunately, the FTC is empowered to do the "old-fashion sleuthing" if they find the accusation has merit on its face.
Disclosing partner and vendor data usage to parents is likely a tricky issue for schools. My guess is the current loophole is more about laziness and lack of mature regulation than any insidious plan by Google to capture data about our kids so they can show more relevant ads.