Is it the case, as I understand it was (and maybe still is) in Spain that there is an 'official' price at which property sales take place, and then an unofficial 'premium' paid in cash ie large bundles of 'Bin Laden' (...everyone knows they are there and what they look like but they have never seen them) €500 notes.

"The future is already here -- it's just not very evenly distributed" William Gibson