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Comment by R_Edward | Hacker News Reader

I don't dispute the claim that there are very competent cashiers all over the place. I just seem to be particularly lucky in finding their counterparts whose greatest usefulness is in flattening the curve.

Also, isn't it a little risky letting someone copy your credit card like that? Even if you trust the cashier not to steal the number, how do you know whether they're destroying the information after they're done with it?

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Those carbon copiers were the way they charged CCs for years before computers, right? So presumably there are a decent number of safeguards built in.

(Disclaimer: I'm 29, so don't really remember a time when those things were commonly used.)

Well, yes, that's the way they did it before computers, but no, the safeguards really weren't there. They used carbon paper to transfer the number from the card to the leaves of the receipt. So when the carbon gets discarded, it becomes trivial for someone downstream of the transaction to pull the carbon out of the trash and use the embedded number to do some internet or telephone-based shopping of his own.

It's funny--29 doesn't sound particularly young, but I'm really suppressing the urge to call you a whippersnapper.

Before widespread communications networks, credit card imprints were taken with machines that look like [1]. They are still sometimes used when networks are down or when there is no phone/Internet network (think temporary locations like fairs and carnivals). The security is that the credit card company will (hopefully) void invalid transactions...

[1] http://img.ehowcdn.com/article-new/ehow/images/a04/b9/g6/cre...

Thats part of the service you get by paying for a credit card. You have the opportunity to review your expenses that month and contest any that you disagree with before you pay for it. On the other hand, if you made the purchase with a debit card, you would have a much harder time trying to reverse the transaction.

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