In an unusual eight months of frequent Ryanair flights between UK and continental European airports, I've noticed that passengers who have paid for priority boarding are accepted at the gate with only a visual inspection of their home printed boarding pass. The barcode that is scanned at security and the gate seems to contain no information about priority boarding.

Now, I'm not a Photoshop genius, but if were to print two boarding passes, one with priority and one without, I reckon it would take me about sixty seconds to doctor the non-priority pass to read 'Priority Q.'

Since I don't care enough to try this out myself, could anyone tell me how Ryanair (or indeed any airline) spots genuine pre-paid priority boarding customers when the only check of that part of the boarding pass is visual?