What will be the benefits to the guarantor? Definitely they will want some returns on what they had put forth. Guarantee still requires funds to be locked up.
...or just assets and general wealth.
I hereby officially back Bitcoin with 1 goat.
Thank you for your participation. But promises are worth nothing. You can change your decision at any time. But public non-profit organization is a different case. It will accept donations and people who have donated will not be able to change their decision.