Of course, when I went shopping, I didn't go as myself. A flask of Polyjuice Potion, some larger robes, one of my mum's hairs, and a put-on accent I learned from dear Viktor, and nobody'd ever believe it was me. Several times I walked right by one of the Weasleys, coming out of Knockturn Alley, and they didn't twig to who I was. The Gringotts" goblins did know, but couldn't have cared less as long as I was the "Hermione Granger" who had money on deposit with them. Even after my shopping spree I had a tidy sum left, which augmented the money my parents give me very nicely indeed.