As evident in the picture, there are two boxes for two separate charities in the lobby of this hotel.The transparent box is marked with the name of a charity committed to
Quite aside from the fact that one of the boxes is transparent and the other opaque, there is very little difference between them as they are right next to one another. Notice that they both have the slot for enabling contribution at the top and are of roughly the same height. It therefore unlikely that one would be able to make a contribution to one purely because the other is beyond reach.
Now to the question that made me take the picture. Given that the only difference between the boxes is that one is transparent and the other opaque, is this material for the contributions received by either charity? It is clear to me that the managers at the Apsara Angkor Hotel have unknowingly set up a fascinating experiment. With their permission, it would be interesting to compare the total contributions that the two charities receive over time in order to know whether the transparency of the box affects contributions. Of course, I make the big assumption that guests are likely to contribute to these charities equally.