By making a copy of your passport anywhere, such as when issuing a new bank card or obtaining a driving license, you are at risk that your data will become public. So it makes no sense to send false documents. Do not send your documents to the airdrop various and questionable ICO.
If you are sending your documents make sure you are sending for exchanges that require those and there is no guarantee that they will be keeping it safe,either way sending in fake documents is just attracting damage ,if something goes wrong they would simply ban your account without even reviewing and if you have coins in the exchange you are doomed. Who would really send the documents for airdrops. 