I have been part of a few airdrops with bad code. Some have completed a swap and others have decided to just shut down the project and start over again.

One really good team for finding bad code is the Ethereum Blue team. They are developing the BLUE wallet, which is supposed to be very secure. One of their goals is to use statistical analysis to find flaws in contract code and warn everyone about them. They found the Etherdelta hack, the Monero Gold scam and the Etherdoge scam. Honestly, they are doing the crypto world a huge favor.