Then, one morning, your local government contact called you:
How are you? Been a while since the last time we talked. By the way, sorry to inform you, but we have decided to give treatment to village X. I know, initially it was a control village. But we thought that the village is in a desperate need to get treatment. So, in fact, we have already started treating village X.And this was not the first time you received that kind of surprise phone call. And out there, many still believe that a big donor like the Bank is a kind of super institution that is able to dictate governments here and there to get what it wants.
Note: anyway, in randomized trial, there are ways to deal with this; you can choose to apply the Intention to Treat analysis, or the Treatment of the Treated.