Thanks for the reply!

In general, I believe that people rely on legal or procedural controls to make sure that the principal portion of an endowment is never withdrawn. But there is always the risk of embezzlement by someone with access to the funds. By destroying the keys on the delegating account, a donor can guaranty that the funds are inaccessible for withdrawal.

But no, for this concept, that step would not be necessary. An institution could use legal and procedural controls, just as with a traditional endowment.