78.3% of statistics are made up on the spot
So you're saying that 40% of those surveyed are too dim to make up a fake password for a £5 voucher? These alleged surveys keep coming up and the same claims are made, without anyone (from the people doing the survey to the journalists who uncritically reproduce the results) apparently considering that 56.98% of people[1] will tell porkies to get free stuff.
Offer me money/vouchers/chocolate/booze and I'll happily give you lots of passwords. I can't promise that any of them will get you anywhere, but they will be passwords...
Of course, it's quite possible that 78.21%[2] of those handing over passwords were completely silly, and gave real ones, but there's no real way of telling, is there?
[1] I'm sure that figure is right. Somebody did a survey....
[2] There was a survey about that, too. Probably