Is that true? If I contribute to a MIT-licensed project without a CLA, my contributions can't just be re-licensed to some proprietary license, can it? Wouldn't my contributions remain MIT, even if they re-license all other parts of the project to some proprietary license?
Isn't the point of CLAs that you can re-license contributors' contributions?
MIT and BSD are so liberal that anyone can commercialize the work. All they have to do is attribute your parts to you, and not demand a warranty of you.
CLAs in those cases may be more to cover their ass in case of disputes about authorship, the future of the project, or in case they forget attribution.
Isn't the point of CLAs that you can re-license contributors' contributions?