Anyone can still accept routes that don't have the stamp of authority. I would also point out that the big authorities handing out the certification for this c

Anyone can still accept routes that don't have the stamp of authority. I would also point out that the big authorities handing out the certification for this can also just revoke your IP block instead. You could still announce the block but since you're not longer in legitimate ownership of the IP block, it's likely that you'll quickly be blocked from announcing it.