Judging by the Wikipedia page, pre-pay e-cash cards.
But as police and criminals are in a constant arms race of what does and doesn’t work, that’s a bit like asking “how did we win wars before atomic bombs?” in a discussion about a country proposing to ban nuclear bombs.
But as police and criminals are in a constant arms race of what does and doesn’t work, that’s a bit like asking “how did we win wars before atomic bombs?” in a discussion about a country proposing to ban nuclear bombs.