I've been turned off many times from contributing because projects had incomplete or inscrutable CLAs. Of course, the person in charge of asking for a CLA signature is usually not very knowledgeable about their own CLA, being a programmer and not a lawyer.
For example, I have been asked to sign CLAs that granted rights to "recipients" or "organizations" that they hadn't named, having simply adopted a template CLA without filling it in. Some placed specific requirements on me, like "notifying the Project Manager", without information on how to do that or who they were. cla-assistant.io even has the unbelievable default of stating that it's a "CLA for multiple repositories or organizations" without naming them. How can you agree to a contract without knowing where it applies?
In my experience it is rarely possible to legally contribute to a project that uses a CLA. You can ignore the legal issue with the assumption that none of it will come up anyway, but that's a weird way to approach contracts.
For example, I have been asked to sign CLAs that granted rights to "recipients" or "organizations" that they hadn't named, having simply adopted a template CLA without filling it in. Some placed specific requirements on me, like "notifying the Project Manager", without information on how to do that or who they were. cla-assistant.io even has the unbelievable default of stating that it's a "CLA for multiple repositories or organizations" without naming them. How can you agree to a contract without knowing where it applies?
In my experience it is rarely possible to legally contribute to a project that uses a CLA. You can ignore the legal issue with the assumption that none of it will come up anyway, but that's a weird way to approach contracts.