That is something that I do worry about. Expulsion from Hogwarts, with formal snapping of the wand, is supposed to cut the expelee off from wizard society. For someone like Draco-the-Inbred-Malfoy, it would be kinder to kill them. For me? Well, unlike the purebloods, I can function just fine in Muggle society, and I've taken precautions. Remember when I said that I'd been turning Dark Arts memorabilia into money down at Borgin and Burke's? Well, some of that money went to buy myself five or six used wands. While Ollivander's the place to go for wands, that doesn't make it the only place one can go. I also laid in supplies of potion ingredients, advanced spellbooks, and other necessities.