A video has been posted on The Telegraph's website showing a woman being thrown off a Ryanair plane by the Guardia Civil (the lowest level of police in Spain): Camera captures Ryanair passenger ejection for 'wrong hand luggage'.
It is understood that the passenger had a book and a scroll in her hand that she couldn't fit in her case, though the airline claims she pushed past staff without showing identification.
Ryanair has a history of being draconian with its baggage policies. The Irish airline was one of the first airlines to see the profit-making potential of ancillary fees and as a result made its baggage allowance smaller than any other airline in Europe to force people to check their bags and pay for the privilege.
I too have caught on my camera phone abuses of power by Ryanair-authorised airport staff. I saw a man's bag fit the airline's baggage allowance but still get forced to pay a fine as the soft material of his bag meant it was a struggle to fit in. See the pictures here: How Strict is Ryanair's Hand Baggage Policy?
See also: Ryanair Fees