Here in the UK civil service they are very keen on peventing that sort of thing - we have a specialist defence fraud unit to combat it, regular business wide presentations, posters on the wall with telephone numbers for anonymous reporting of suspicious incidents and any hospitality, gifts etc have to be declared in the books provided for the purpose.

Maybe it is bureaucracy going too far but it presents an image of fair competition for tenders (and there is a whole process and tender boards just for receiving those and ensuring no frauds by employees replacing pages etc etc.)