Current regulations allow passengers to take a carrier bag of goods purchased in the airport on board as well as their hand luggage. The only reasons for denying passengers this right are based on weight or security reasons.
It seems that some airlines, including Ryanair, have been telling passengers at Barajas that they can only bring one item of hand luggage on board. They are being denied the right to bring an additional carrier bag with goods purchased in the airport into the cabin.
I can see their issue, some passengers travel with the maximum size of cabin luggage allowed and then purchase more goods in the airport and so have a large carrier bag as well. There is only so much room in the overhead bins and they do fill up quickly, that is why some airlines now encourage you to put your cabin baggage in the hold. Of course, if there are items in your cabin bag that you either need during the flight or do not trust to the hold then that is a no no.
When we fly to the UK for our daughter’s wedding, I’ll be taking all my camera gear in a cabin sized bag. There is no way that I want that precious cargo to be thrown around in the hold. There isn’t room in that bag for anything I buy at the airport so I might just have to be circumspect even though we are NOT flying with Ryanair.