Kind of short sighted only consider social cancellation. People in power change, laws get applied retroactively. History is full of people who get purged from stuff that was fine when it was written
you can intentionally add false biographical information. what if you had a bot posting responses in subreddits for cities across the world on your account
The US has had mail in voting for 100 years with no widespread fraud. You're going to have to present more evidence then "what if bad actors use it this way"
Further more, know your neighbors, join mutual aid groups, build social connections before bad things happen. The idea of a single prepper surviving the apocalypse is a farce, humans work in communities.