Maybe that will not be a scam but most people will still considered that is scam reminds they are not asked to pay some TON before the the airdrop gives. The owner of the project must clarify the procedure to people before they run the airdrop programs so people will not be misunderstanding with the rules. I guess that is miscommunication between the teams and people who want to do many tasks to get the rewards from the airdrop. If the teams can explain about the requirement before they run the project, maybe the misunderstanding will not happen. People will choose the project by themselves and will decide if they want to pay some TON as fees or will search the airdrop programs that will be free.