So...it's more efficient for the central transaction processor (bank) to try and verify the legitimacy of transactions, rather than each individual? Let's break that down.
Let's just take an imaginary small consumer bank, with 10,000 customers in a local community. If we assume that, on average, their customers all have debit cards and use them to the tune of 20 times a week, that brings us right away to 200,000 transactions that the bank has to review and analyze per week. In the course of a month, it's 6,000,000.
So, how can the bank determine fraudulent transactions? Well, they can try and baseline everyone's average buying habits (stores, categories of purchasing), but that could cause false positives as people very often do unusual things. They can try and flag transactions based upon the use of the card in unusual places, but with so much interstate and even international commerce thanks to the Internet, that's not such a sure sign either, now.
Let's not forget that with a small bank, they don't have big and fancy computers with trained analysts to throw at the problem. I would think such small institutions have a staff on the order of a couple of hundred people, at best?
Of course, the big banks certainly have the money to throw at the problem to buy proper computers, software, and hire enough analysts, but the complexity is now far, far worse, as they service millions of customers all over the country (and possibly/probably international). Now we're talking probably in excess of billions of transactions for the same time period, and I think it's safe to say the complexity rockets up at an exponential rate, as you're now dealing with the rich, the poor, and everyone in between, all with their own buying patterns, habits, life changes, etc.
So, it's easier for the banks to be responsible for analyzing EVERYBODY'S transactions, which are complete black boxes to them?
Or, is it easier for us to log into our online account once or twice a week, scan our virtual checkbooks of 20(ish) transactions and say, "Yup, I remember buying all that stuff"...?
Whatever happened to taking a little personal responsibility?
For my part, I've been using Quicken for almost 5 years now to track every single account I have in my name, from mortgage to checking to retirement funds and all the rest. I'd venture to say nothing happens in my accounts without me noticing it in a few days. (It's a nice feeling to have such total understanding of your complete financial situation at any given moment. ;-) Sure, it takes some discipline, but after a while, it becomes habit.
About that comment you linked? Interesting, and he makes a good point about identity theft - but that's not what we're talking about here.
The case of the original poster was simple theft. Yes, the debit card number was lost, but it wasn't his SSN or some other critical piece of Personally Identifiable Information that allowed the thief to then take out a loan in the guy's name and walk off with the money, never to be heard from again and ruining that victim's credit rating in the process while leaving him personally liable for a debt he probably could never cover.
I'm not sure I see what liability for identity theft has to do with the efficiencies of who should be ultimately responsible for monitoring an individual's banking transactions for fraud.