I would devote an amount of energy to avoiding that scenario that seemed commensurate with its expected value. Indeed, I'm doing so right now (EDIT: actually, on consideration, I'm devoting far more energy to it than it merits). If my estimate of the likelihood of you obtaining such a wand (and, presumably, finding the one person in the world who is suffering incrementally more than anyone else and alleviating his or her suffering with it) increases, the amount of energy I devote to avoiding it might also increase.