Change the currency, not the printers (Score 1)

From my experience of US bills, being all the
same size and colour, and printed on paper,
I'd guess it'd be easy to fool a well chosen
victim in dim lighting with a photocopy.

However, here in New Zealand (and Australia),
apart from be coming in various sizes and colours
our notes are plastic with transparent windows
and fancy textured patches. I've also seen
European notes with similar features.

Perhaps making the currency less susceptible to
copying would be more palatable (to some).

Of course this only addresses of the targets of
digital watermarking.