If they are big influencers then a lot of people will follow their moves and try to do the same. But as some users already say, they could use their followers to bump any shit coin. That's why I wouldn't recommend following them in their transactions.

For a good example of a Twitter influencer who can manipulate the crypto markets, we have Elon Musk, even a user on this forum made a bot to buy BTC each time that Mr. Musk post on Twitter.