This has happened to us now two years in a row. If you miss a booked flight and are treated as a 'no show', you greatly increase your chances of getting a secondary airport screening. It will show as "SSSS" on your boarding pass the next time you fly.
Last year our flight from Rhodes to Athens was canceled due to weather, which meant we didn't catch our flight the next day to the USA. These were separate tickets, which were purchased as non-refundable. I had checked in for the home return flight at the Rhodes airport, before we got the cancellation notification. We flew out of Rhodes the next day and purchased new flights home for the following day. However, we didn't cancel our original flight home. Travel insurance paid for the new tickets, overnight stay, and meals. The extra screening was at the Athens airport for me.
This year my wife got sick in Scotland and was in the hospital when our original return flight home was scheduled. Again, the tickets were non-refundable, so I didn't attempt to cancel the flight. I had a lot going on already. We eventually flew home 3 days later after purchasing more expensive tickets on a flight where we could have 2 seats for ourselves in our row. Travel insurance should pay for the additional accommodations, medical bills, meals, and the flight home. My wife was in a wheelchair and she was flagged for the extra screening this time at the Dublin airport.
The Dublin security said the extra screening is based on an individual's profile, flying history, and more.