Best to trust PIREPS
But how to obtain one unless the pilot tests the conditions first? Chickens and eggs?
Whilst, in the UK, ATC will not give a braking action report on a contaminated runway, I believe our Scandinavian colleagues try to be a little more forthcoming. With the odd exception, this seems to work and those airlines based in the North tend to use their hard won expertise to operate efficiently within the constraints of their environment.
It seems a little harsh to castigate MyTravel AS for their upset in this case - they are a proud and excellent airline with a long history going back through many name changes, but with the same safety conscious ethos. Their tie in to MyTravel AW is in the same commercial vein as, say, Thomas Cook AW to their German cousins - same livery, different airline.
There again, this is PPRUNE!