Similarly (arguably worse) someone can create a drop box account using your email address and there is no verification nor mechanism to say that it is not yours. Their support will repeatedly bug you to use an automated system, and of course the automated system cannot fathom that you do not have or want an account. I think it took a couple of weeks for them to actually delete it. Alternatively you could try the lost password flow, log in and delete all the files belonging to the poor sap that made a typo. All the while, you hope none of those files were intended for you.