Surely there is a middle ground for contributions which you don't really care to retain ownership of? I don't sign CLAs for projects I want to form a long term contributor relationship with, but if I am just trying to fix a small bug that the (probably corporate) owners don't care to fix themselves, I'll sign that code away without hesitation.
FWIW CLAs do not sign away your ownership in code. It merely gives the project the right to use your code via a license
You know how you sign those end-user *license* agreements, which do not give you ownership in the code of those applications?
That's the same principle at work here. You are licensing certain rights in your work to another entity. Generally, the license is giving the right to, inter alia, reproduce and distribute your code in perpetuity.
