Ive seen those situations too which you would need up to send some fees or amounts for them to able to push transactions on sending out tokens but i do see really a dumb thing to do. Airdrop would always been free and this is one of the ways on how to market their tokens.Theres no point on asking out fees because this would really be their obligation and they should have the fund for them to make use of it.
Whatever it is if the airdrop/marketing team of that token requires of any amount to be sent, it's your own will to follow.
But I'll never send any amount if they ask, I'm not a die hard fan of airdrop.