These incidents are always infuriating to hear about. Every company in the world (whether they are writing software or not) needs a bug bounty program.<p>Although Starbucks is on HackerOne now, so hopefully things are better.<p>As an aside - "would easily make me a couple of millions of dollars" is definitely not true. Discrepancies even in the thousands of dollars would be caught pretty quicky by their accounting software, so please don't be tempted to try this.