1. Paul gets a really bad cold.
2. Paul's bank cards get cancelled.
3. Daniel's bank card gets cancelled.
4. Daniel puts all his money on a travel visa, then gets locked out of his account.
5. Pete does the same and is also locked out.
6. Pete loses his bag, then loses his boarding pass within 60 seconds of attempting to board, goes back for the bag, can't get on plane, needs new boarding pass.
Nothing can possibli go wrong.