What does "Remember my last, Petunia" mean in Harry Potter and the Order of the Phoenix?
From what I gather, most people seem to think it refers to the letter Dumbledore left for Aunt Petunia when he left Harry at the Dursleys' doorstep -- but is it?
Aunt Petunia seems to act as if she was compelled to keep Harry at her home after listening to the Howler, but what would compel her to keep him there?
Uncle Vernon had, I suppose, made a logical decision to throw Harry out after he found out that a dangerous criminal was looking for Harry, and Harry certainly couldn't call it his home if the owner did not let him live there, which was the sole cause of the existence of the protection. Could it be that the charms that protected Harry from Voldemort at the home of his relatives was also protecting his relatives as well?
But then again, did Voldemort know about the Dursleys at all? He probably would have tried to find out where Harry went when he was away from Hogwarts, and the Ministry certainly knew where Harry was and with whom. Even if we believe Voldemort and any of his crew didn't know about the Dursleys prior to the Order of the Phoenix, Lucius Malfoy did have good connections and a certain level of control and influence over at the Ministry. Wouldn't it have been possible for him to find out about Harry's relatives after the Ministry decided to go against Dumbledore at the end of Goblet of Fire?
In Deathly Hallows, Harry states that the Dursleys should go into hiding because Voldemort might try to take them hostage to make Harry come and save them, so the Order itself takes it upon themselves to ensure the Dursleys' protection.
Even if we assume that all of the residents couldn't be harmed inside No. 4 Privet Drive (and not just Harry) by Voldemort, wouldn't it be easy for him to, say, attack uncle Vernon at the office or Dudley at school? They certainly knew about the general location of the house, wouldn't they know exactly who the residents were and where they worked?