simple answer:
0 confirmation transactions are safer than you think, its still way harder than chargeback on a credit card
starbucks has cameras, if you steal from them than they call the police
Yes, another elegant way to put it. Plus, just because your bitcoins are anonymous to an extent in your wallet, who's to say most companies won't ask for ID before you make your bitcoin payment. So if you were to double spend, they'd at least have a photo ID scanned to send to the police. Double spending is also not THAT easy to do.