Snape planterade inte idén att flytta Harry tidigt. Det var redan Orderens plan, som Snape läckte till Death Eaters på Dumbledores råd:
"You will have to give Voldemort the correct date of Harry's departure from his aunt and uncle's," said Dumbledore. "Not to do so will raise suspicion, when Voldemort believes you so well informed. However, you must plant the idea of decoys; that, I think, ought to ensure Harry's safety."
Observera att det var tanken på devisningarna, inte tidpunkten för flytten, som Snape skulle plantera.