It'd be kinda nifty if GitHub had this built-in. I personally don't require CLAs for every project because it can be onerous. But at the least I try to pick a license that wouldn't allow for submarine patent claims.
I've wondered for years why GitHub doesn't provide a license field as part of the repo along side name and description. I've been known to pester people after they point me to their repo, and ask them to add a license before I'll use their code. Automating CLAs would be a dream.
