I think it is probably generally accepted that the European "tax-net" is tightening & that the "good old days" are at an end for most people. And of course following the EasyJet debacle this was always going to be the next target, why else do you think FR never opened a BVA base, just TOO visible on AF's doorstep.
In the beginning most contractors made a conscious choice to go down this route for "tax optimisation"
regretably it degenerated into a situation whereby FR benefitted (& the employee lost out) by making no social contributions & it rapidly became the only show in the FR town with no permanent contracts on offer.
The arguments by various "legacy carriers" that FR enjoyed an unfair advantage by "social dumping" is entirely valid, and one that the pilot were happy to go along with as long as it was of benefit to them in the short term.
Like everything else in the FR"I'm all right jack fcuk the rest of you" business /employment model, this has come back to bite those who profited by it.
For now the pilots are paying the price & it will be the turn of FR one day too, as more Govt's catch on to the untapped revenue source existing in their backyard. Of course FR will expect the employee to bear the brunt of the additional contribution burden, or will try moving to more "cooperative" tax regimes, but, Europe is only so big, and you "can run but you can't hide" will eventually come to pass.
Still, "good while it lasted" has to be the "glass-half-full" motto for both contractors & Ryanair alike I guess.