'The vast majority of charter school operators have nothing in common with phone scammers, but the same basic market principle applies . -- if scammers get a return on even one hit out of 10,000, that’s more than enough to keep them in business. A charter school doesn’t need to corner a market; it needs to attract just enough customers to keep the business going. A charter school doesn’t need to serve the entire market; a public school does. Public schools are tasked with keeping everybody happy; charter schools just need to reach enough families to fill the seats they have.The notion that parents can exert some sort of accountability pressure on any but the most terribly run charters seems unlikely. It is one advantage that charters have over public schools; charter school families are easily replaced, while public school families are not'