In the event of e.g. massive snow cancellations, major airports can normally conjure up camp beds, blankets etc. It’s not their responsibility – under R261 the airlines should already have bussed their stranded passengers off to nice cosy hotels, but it’s yet another measure of the madness of R261 that it assumes that hotel rooms can be found for 5000 passengers caught in a whiteout.
I think you can reasonably assume that the cost of the camp beds and blankets will be passed on to the airport’s customers – i.e. the airlines – through their charging system … and consequently into the airlines’ pricing system.