It very much is to protect vulnerable customers, but it’s not wholly altruistic. UK Banks are (mostly) required to make customers whole if they’ve been defrauded unless they’ve been grossly negligent. The banks have tried to interpret the “gross” part fairly broadly but the regulator and Financial Ombudsman (legally mandated arbitration for consumers where that’s actually a good thing) interpret “gross” as more extreme than “almost anything”. The result of which is that banks are keen to show that they took every possible step to prevent someone being scammed - whether popping up notices during online payments, or asking in person. If they don’t, they can very easily be required to reimburse the customer themselves.

Edit: digging up a citation suggests that it might be a voluntary code that banks are signed up to [1], but the regulatory regime has still swung much more in favor of the customer.

[1] https://www.citizensadvice.org.uk/debt-and-money/banking/ban...

Certainly not the whole reason, these days. But having known a few extremely gullible people, who were blatantly scammed out of thousands of dollars, it is enough reason.

I also get asked this questions if I buy gift cards at the supermarket or pharmacy these days. They have to "unlock" the card at their computer, so they ask if it's really for a gift or if it's some shady person on the phone.

If you watched Kitboga videos on Youtube, you know scammers often ask for gift cards as payment.

I didn't know this was a practice but I suspect some of it might be to detect overly trusting elderly people being ripped off. If it prevents some of that then it's probably a good thing.

That's true for large amounts and there are a lot of scams so it makes sense. But this is around small denominations - I was only getting a few hundred GBP in £5s for a festival.