The time for Ryanair will come when these secondary airports used realise that, to make a profit themselves, they will have to charge a realistic landing/passenger fee.
In addition the European Commission will see these so called "marketing" payments for what they really are - subsidies. EC law requires that subsidies are subject to a tender process.
What then for the FR profit margin? If prices go up, the attraction of using secondary airports will diminish except for those people where the airports is genuinely the most convenient for their requirements.
EZYs spat with Luton should remind budget airlines that they cannot expect the airports to subsidise their operations ad infinitum.
I still think that, should FR put their fares up on EDI/GLA to DUB after GOs withdrawal, there will be a very good court case for predatory pricing This would especially apply for EDI to DUB as MOL has clearly stated in the past that this route was not under consideration due to rapacious fees from BAA, but quickly changed his mind when the upstart airline had the temerity to challenge his monopoly.
Hugo