The bar would have to eat the transaction risk, at least until the first confirmation (typically under 30 minutes). On the other hand, if they accept any other

The bar would have to eat the transaction risk, at least until the first confirmation (typically under 30 minutes). On the other hand, if they accept any other form of payment besides cash in hand then they are already accepting that risk in the form of chargebacks—which can occur months after the transaction. The scenario in this article is akin to opening a brand-new account at your local bank and then trying to spend from it with a debit card immediately afterward. You're likely to incur an overdraft penalty, if the transaction isn't simply declined. If you want to pay with Bitcoin you need to have Bitcoin—confirmed—at the the time you make the payment. This is not a problem in practice but it can trip up people experimenting with the system for the first time.