Some Open Source projects require their contributors to execute so called Contributor Agreements. The content of these agreements vary, but many address contributors right to make the contribution and some assign copyright in the contribution to the project or some individual or organisation representing the project.
It appears to me that none of these agreements fulfill the requirement of consideration necessary for enforceability under UK/US law. I am aware that the bar for consideration is low, but to me it appears as if this category of agreements as general rule present no argument what so ever for passing it.
Am I missing any obvious counter arguments?
I have provided links to some example Contributor Agreements below. None appear to me to specify any consideration for the contributor that would qualify under US/UK law. The Qt agreement does mention consideration, but none is to be found in the substance of the agreement.