Well not all airdrops project that demands people to pay some little amount of money are scam because even genuine projects in the past that actually airdropped did requested for their participants to pay a little token before becoming completely eligible. It's just bad that there are many scam airdrop projects out there than the genuine ones hence the discouragement whenever the idea of paying money as part of task is initiated because it's difficult to differentiate between the genuine from the fake until they eventually airdropped.

My thought is that these projects can just state it from the early stage that they will be demanding from their participants to pay some TON fee at towards the end of the entire tapping and task fulfilments, and not to take people by surprise when they never expected it that way.