So if the government decided that it didn't like someone who has said something that the deem to be "anti vax" at any time in the future, what is stopping them

So if the government decided that it didn't like someone who has said something that the deem to be "anti vax" at any time in the future, what is stopping them from getting someone to say "I saw that thing that he said several years ago, and that convinced me not to get jabbed up? Nobody would be able to prove that not to be the case and the" anti-vaxer" that the government doesn't like can then be prosecuted with no defence. This is clearly government over-reach and designed to target anyone that doesn't follow their narrative.