Think about another crazy scenario, in fucking plain sight:

• you choose specific height blocks
• in each one, you put a OP_RETURN with one word inserted into a simple sentence. Not just the word, will be too obvious for OP_Return watchers.
• 12 blocks in a specific order, that only you know it

See? You can recover that info anytime you want and nobody will know that is a seed right on the blockchain. And is there forever.