yes, some people do, also since many people who launch/control coins (and possibly exchanges) want to create or push some perception on others they use fake accounts /multiple accounts to spread rumors, lies, whatever.
The greater fool theory of economics.....
Would you buy a bag of oranges for $50 ?
If you knew you could sell them to a 'greater fool' for $100 , you would.
Apply that.
Greed is what fuels it all