There is a difference between making a promise and being bound to a contract. If the idea was to not make a profit from the pre-mined tokens and / or use these for a specific purpose, why wheren't these tokens parked in a non-profit organisation?
Say the value of the tokens would be several million US dollars. If these tokens are owned by an ltd, then what stops the share holders of that ltd to cash out the tokens and pay a nice dividend to themselves?