Multiple notarized copies, just to ensure it hasn't been altered. If you do alter it, again make sure there are multiple copies and that it contains verbiage that it supersedes the previous document
Not a lawyer, not legal advice, you know the drill. However, the above is from my lawyer and is the policy I follow. He witnesses it AND it is notarized by a third party.
In terms of bizarre things family members have done to inherit things, this sort of escapade probably wouldn't even breach the top 100.