Some people knows about this doubling scheme, of course it's a scam but using the accounts of the big names offers to double their bitcoin or cryptos then you really think it's legit. Hackers are really taking advantage using the accounts of influencers.
You're correct, those scammers cut many unaware, because of these notable twitter accounts they hacked into to carry out their evill acts. Even the elite in the world of cryptocurrency were not alerted as many fell for this before the news went viral on social medias about the hacks. Those scammers understand the greediness that's with humans, and took the opportunity to scam gullible cryptocurrency holders.