Yes...low cost carriers. Happy for the price but I was surprised by a recent experience I had with Iberia Air. It's very important that you check in online as soon as it is possible to do so for your flight and get that boarding pass and seat assignment! I had multi connections in my journey to Santiago and couldn't check in online for the Iberia, Madrid to Santiago leg before I left home.
When I tried to check in during two following layovers, I couldn't get on the website. When I arrived in Madrid, 2 hours before my Iberia flight, I checked in at a kiosk and was given a standby boarding pass and was ultimately bumped off the flight at the gate. Iberia overbooks considerably - there were about 25 people with paid tickets who could not get on that flight.
I did ultimately get compensated with an overnight hotel room, meal vouchers, transport from and to the airport, and 250 euro. Grateful for that but it was a very confusing almost 3 hour chaotic process getting the compensation - waiting in lines and getting shuffled to different customer service counters. I was given a flight out the next morning but it altered the plans for the start of my camino which all things considered wasn't as bad as some other folks I talked to who were missing family events that were happening that evening.
This overbooking policy seems like fraud to me. In booking and purchasing a ticket you enter into a contract that should be honoured. It is also extremely tough on the front line employees who aren't responsible for making the policy. The anger and abuse that I witnessed being directed toward them must be incredibly stressful to deal with daily.