It also significantly deters people from ever modifying that code and using it commercial applications, even if they are willing to open it up sometime in the f

It also significantly deters people from ever modifying that code and using it commercial applications, even if they are willing to open it up sometime in the future. (Believe me, as a several-time CTO, I've wound up in every case deciding that modifying virally-licensed code is way more trouble that it could ever be worth...)