I think this is absolutely vital. Think tanks present themselves as groups of experts in a field who come up with independent solutions to problems. However, many think tanks are in fact funded by organizations with a heavy bias on one side of a particular argument. This has the capability to sway a think tanks thinking, so it is vital to take their source of funding into account when assessing their output.
yes, i do think that sources of funding need to be revealed by think tanks. I think that these methods are usually the ones that work really good, and that they are the ones that will make the best ways to help all of us out with the money issue.
Generally speaking, transparency regarding finances and knowledge are good. Think tanks represent the nexus of this. Revealing funding sources might reveal biases or reasons for writing, and there should be no reason to be embarassed to be revealed as someone who funds think tanks. It should be a point of pride.
People should know, because they do not want to be giving information to people who are just trying to make their lives harder. If someone is struggling in their life right now. They may be on food stamps, or something. The person does not want to provide information of how they can get the government to cut those food stamps. Think tanks can be very shady and may be trying to hurt the people that are trying to help them.
If you do not like the message sent by a think tank, their methodology, or their agenda, you need to dissect those aspects of their papers and recommendations. Knowing who writes what check does not provide a basis for refutation of ideas, only the ability to use fallacies in attacking proposals. Ideas cannot be wrong because of who supports them, only if they lack reason and evidence.