If you are talking about airdrop then most of the airdrops are fake and never get listed on the market which the owner thinks that they would and he makes that token in order to sell that on exchange when it gets listed to get a profit for risking just a small amount of money. But the fake ICO are now a days pretty hard to identify as the scammers also spend a lot of money in marketing and making fake profiles of team members, so it's pretty hard to identify a fake ICO.