It's not that Dumbledore sends Harry back to the Dursleys' and modifying memories every time he runs away or gets taken away by social services--it's the wards (which may or may not have been created or altered by Dumbledore in the name of the greater good/Harry's safety from kidnappers). But if the wards are doing it, they're not exactly going to stop when it's time for Harry to go to Hogwarts, are they?