This is a very poor advice at deniable encryption. The structure of the ciphertext is visible to the reader - when you get your decryption you know that it is one of many.

I presume the true deniable decryption would work in a way that fully hides the presence of the alternate contents. Note, however, that most encryption schemes are specifically designed to be non-deniable, so you'd be caught by simply using organically grown crypto before even decrypting anything.

For those interested in paranoia, I suggest looking into steganography and forward-secrecy schemes with transient secrets.