I think the whole thing comes down to trust....

What guarantee do we have that the bitcoin are actually going towards that project? Let me make an example and then you tell me if it is possible to do this or not.

Ok, let's say I take photo's of someone else's project or even just the land that are being worked by those people and I say that this is a project funded by the Bitcoin donations that are being donated on this forum. (Will that be possible?)

What proof can be given that our donations will go towards that project? ( I love the idea, because you are helping them to fish and you are not simply buying the fish for them)