Airdrops were so popular among the crypto-community over the years. One of the key features of the airdrops is, it gives every participant a chance to get some free tokens by completing few tasks. Most importantly it is totally free of charge. But nowadays we frequently see a trend where the organizers of some of the airdrops ask to send a small fee prior to sending the tokens. In some cases, they put a condition saying that in order to withdraw tokens or any fund received from the sale of tokens, it is mandatory to take part in their ICOs. I would rather call such events as "Scam-drops" as they not only dilute the meaning of airdrops, but also make people to move away from future events due to lack of trust.
Its actually alarming that something that was so great at promoting Cryptocurrencies became a target for people who wants to take advantage of other people. Airdrops are really helpful to create a hype from an upcoming platform since some tokens can really boosts their value because of its demand. The Scam-drops only started when some platforms wanted the people to pay for their own gas fee to obtain the free cryptocurrency. This became a trend within Airdrops and now most people are scared of joining legitimate airdrops.