I would think from a legal perspective (NYS law) it would be difficult to keep a charter school open that openly violates established law and procedures. Like a school can institute corporal punishment, and it may work, but I think the school still might get shut down.
I wouldn't go as far to say most schools are cheating, because I don't know, but I will say this - the charter school argument rests solely upon the premise that it is a better taxpayer investment than public schools. Not simply a better monetary investment, but management and teaching by private interests are far superior than public workers. I don't even know if this is cheating - it's literally choosing a team of ringers. It's like playing dodgeball against a team of MLB all-star pitchers. They are taking the kids who would succeed in public schools anyway, putting them in charter schools and saying, hey, look, we did a great job. It's more than cheating, because charter schools need not exist for people be educators or keep their jobs. The very existence of the charter school model, which is and should be very much in debate, is what they are attempting to preserve that further serves to undemine public institutions.