I went to a Subway shop that charged $50 per lettuce strip past the first 20. As the worker sprinkled lettuce on my sandwich, I counted anxiously, biting my nails. 19, phew, I'm safe. I think I'll come back here tomorrow.
Tomorrow, someone in front of me asked for extra lettuce. The worker got confused and put it on my sandwich. I was charged $1000. Drat.
> The worker got confused and put it on my sandwich.
No, this is where you're completely and totally incorrect. There is no 'worker accidentally making a human mistake that costs you money' here. This is a 'multi-billion dollar company routinely runs scripts that they KNOW cost you money, but do it anyways because it generates profit for them'. To fix your example,
You RUN a Subway that sells sandwiches. Your lettuce provider charges you $1 per piece of lettuce. Your average customer is given $1 worth of lettuce in their sub. One customer keeps coming in, reaching over the counter, and grabbing handfuls of lettuce. You cannot ban this customer because they routinely put on disguises and ignore your signs saying 'NO EXTRA LETTUCE'. Eventually this bankrupts you, forces you to stop serving lettuce in your subs entirely, or you have to put up bars (eg, Cloudflare) over your lettuce bins.