Star ratings should also factor transferability, aka, the recruiting services should spend the time to talk to HS coaches and found out if kids are on track academically. They don't need exact transcripts, just talk to the coaches. Most won't lie and if they do then their crdibility will be detroyed any way. Good example is last year with Samia from San Ramon, Williams from Liberty, Harris from Clayton and Williams from De La Salle.
Not a sure fire way, but better then not factoring it at all. By not taking the time, you are doing a disservice to guys that are taking care of business in the classroom, and being overlooked because a guy at his position has a four star rating but is going to Laney JC next year.