Well, there's not really any way someone could execute this attack. Receipts aren't logically grouped by reports based on someone's identity... They said it was

Well, there's not really any way someone could execute this attack. Receipts aren't logically grouped by reports based on someone's identity... They said it was part of an experiment and only included a small group of free users (if you're not paying, then YOU'RE the product) plus their employees.