What's weird is that that developer/ webmaster, even if we assume they're completely crooked & egoistic, also has incentive to keep the customer -- in this case UNESCO. As soon as UNESCO understands this issue they might fire whoeever's responsible (if still around). Maybe the chance to be uncovered will increase with coverage of some of these cases, raising awareness among organizations... just as many organizations had to learn that SEO's aren't always doing good, and need to be watched. Then the risk for the developer to hide links will increase as well.

How many people really get into their website's code once it's finished, unless they employ a webmaster? Many people pay for a website and update it with a content manager, without ever viewing the source code. And even if they did, they probably wouldn't know what to look for anyway. The web is a paradise for "crackers," and something must be done.