'We have detected fraudulent activity, call us back with the number on the card.'
You hang up. They don't. You pick up the phone, and dial the number on the card.
Depending on how landline phone routing works in your area, you hanging up does not end the call. You picking up the phone again resumes the previous call, you dialing some numbers does nothing, the scammer makes some telephony noises, and goes ahead and resumes their conversation with you.
Nothing to fall for, eh?
Also, please keep in mind, we are apes. The logical centers of our brains turn off when your bank calls you to tell you that you are being robbed. Especially if your mind isn't as sharp as it used to be.
You'd probably have better luck calling the bank and trying to persuade them.
And again, this isn't about you. Most of the time, you don't pay for fraud, the bank does. That means that your bank is incentevised to reduce fraud, at the expense of your convenience - because not all of their customers are as smart as you are.
Do you have a scam in mind that doesn't depend on a rampaging time machine forcing me back to the 1990s? I don't think I've used an analog land line for decades, and I definitely don't know anyone who has one now.
You don't need a time machine to find one, you just need to leave the young techie bubble.
> I don't think I've used an analog land line for decades
You were cellphone-only since at least 2001? If you spent any time talking on the phone back then, your monthly bills must have been staggering.
What? Seriously? There's nothing to fall for here.
You should never trust an inbound call. If your bank calls you, you take their information, immediately hang up, find the banks phone line and call that number back yourself.