Memo 2012-198 (2012), an S corporation failed to properly document a donated conservation easement because no contemporaneous acknowledgement was received by the donee indicating whether any value had been given to the donor in exchange for the contribution.
Also, consider adding a provision to give a specific person--say a friend or relative--visitation rights if you're hospitalized. (Otherwise, hospitals might impose restrictive visitation policies.) You may also want to spell out your wishes about organ donation--for example, state if you want your agent to keep you on life support while waiting for a donee match.