To think that the creator co-signs on the trust documents is a mistake. This is not the case. Remember, as we have said, the creator (settlor) relinquishes authority at the beginning of the trust. Yes, you are right -- if the creator were to have signatory power over the whole trust, it would place its assets at great risk. In fact, that would transform it from an irrevocable trust into a revocable one. That is precisely why good Natural Law Trusts are irrevocable. By having the creator relinquish control at the beginning, it makes the assets irrevocably protected within the trust.
A funny story about this occurred in 2013, when a trustee went to a branch of Chase Bank to open an account. The bank refused to open the account on the basis that the trust gave the settlor no signatory authority over the entire trust. When we communicated this to our trust writer, he laughed and said "Of course that is what they would like! By giving the creator signatory power over the whole trust, it makes it a 'grantor trust' -- and it is thus revocable. It makes it a lot easier to penetrate and get at its assets." So, that is why the good Natural Law Trusts are irrevocable.