[bambax]

> it essentially cancels out

If the person before me pays for my meal, I won't feel obliged to pay for the person after me.

How does it even work anyway? How do you know how much the person after you owes? It may work at drive ins but it's certainly impossible at a normal queue -- except if people leave a "standard amount" regardless of what the next order actually is.

And even at a drive-in where the amount of the next order is known, it's probably a big hassle for the cashier -- if not downright impossible: the point-of-sale system wants the exact amount if paid by card, and if using cash it's even more complex (the POS system tells the cashier how much to give back, and now this is false and has to be somewhat reconciled at the end of the day).

This sounds completely fake.

[dionidium]

You're right that it's specific to drive-thrus. The implication is that the person behind you has already spoke their order into the box by the time you pay for yours, so the cost is completely known to all parties. It's pretty straightforward.

[blahedo]

It's not a big hassle at all. The system is already managing payments as a queue, and once your meal is paid for (either because you paid it or because you were a beneficiary of someone else), the next one on the queue is the one immediately after you, which the cashier can then take your payment for and clear it out of the system.