Airdrop is supposed to be a free money paid for performing very simple tasks that does not cost anyone money except time and internet subscription. But when it shifts from this to something else such as making payment or paying for withdrawal fees, then it is a sign of scam and most likely a scam. I saw this airdrop but I never though a time will come when they will require participants to send TON to an address as part of the task and now that I know, it is obvious they are up to something that is not good. I will advise everyone to be careful of things like this to avoid regrets.
Yes, we do have to be more careful in choosing airdrops, sometimes there are withdrawal fees, which are actually legitimate as long as they do not exceed what we can afford, but it is still doubtful, yes, if possible, do not trust it to avoid all of that which is certainly detrimental to airdrop users.