Not every undesirable behavior can be blocked by firm rules without catching non-problematic behavior. Using a license which that errs on the side of being permissive rather than restrictive at the boundary and using social pressure to try to mitigate undesirable behavior in that boundary area seems a reasonable approach. (True for law, too, and lots of other domains.)

There's some domains where you need to (given that perfect calibration is unattainable) err on the side of being restrictive, but that's definitely not always the right choice.