Lol, dat is inderdaad wel ongelofelijk. Het staat wel op de website van Riga Airport:
How big is the charge and who must pay it?
The airlines must include this charge into the ticket price; however, the carrier RYANAIR did not agree to include the charge into its ticket price, therefore Riga Airport will collect the charge instead of the airline. Only the RYANAIRT passengers will have this additional inconvenience. The amount of the security charge for RYANAIR passengers is 7 euros*, payable by departing passengers before departure.
If the passenger pays the security charge via the airline, the amount of the charge is 6.5 euros or 4.57 lats.
if the airport collects the security charge, the amount of the charge is 7 euros or 4.92 lats. This amount is payable only by the RYANAIR passengers.