If they ask for the fee for the participant of airdrop them people should not go with it since it's a huge he scam since if they have a good capital for marketing they can afford and boost up their business. And we should be my re careful since I still so many scammer try different things to scam newbies.
It happened before right? I've seen those airdroppers that were complaining that the management of the airdrop they have joined were asking for a fee so that they can easily transfer the tokens to them. They want to avoid the transfer fees which was small to think of.
But it's all found out that when an airdrop asks for that payment for the fees and gateway to transfer the reward/airdrop, you should be more cautious of what you're trying to push. And the fee that I have described was about the "subscription" for whatever purpose they are charging so if somebody is on that, avoid it and get out of that group.