Some of these attacks leave a calling card sort of thing, e.g. a database with a document that says "hey, lock your stuff up". That's more or less the best you

Some of these attacks leave a calling card sort of thing, e.g. a database with a document that says "hey, lock your stuff up". That's more or less the best you can do without unreasonable effort, and there's no guarantee the database's owners will ever see the extra database unless you also destroy stuff on the way to make them pay attention...