You may be interested to know that HIVE/STEEM has already been compromised in a similar fashion by being able to embed images into their blockchain using base64 encryption. You can see my demonstration via:

@novacadian/base64-encryption-explained

Of course the witness cabal could do some type of rollback mischief like was done during the STEEM fork, yet it would be just fingers in the dyke to a determined hacker with a grudge against HIVE.