The latest METAR I could find for San Carlos de Bariloche says:
SAZS 061800Z 32007KT 1000 VA VV/// 07/04 Q1012
So, they do have an ash problem. However, as the airfield is 53 nm from the volcano, this is hardly surprising. Remember that Chile is a very narrow country - the volcano is 10 nm from the Argentine border and 75 nm from the Pacific in the opposite direction...
And, even we ash cloud unbelievers know that ash doesn't respect national borders.
FWIW I still think that in this isolated case MOL will be proved closer to the truth than some of the "authorities" (much as it pains everyone, including me, to admit it).
I'm surprised that no one on this or the Iceland thread has mentioned the appointment of an Ash Czar:
BBC News - Volcanic ash scientist appointed by government. I shouldn't be flippant because I really hope that some independent scrutiny (which isn't about getting extra funding for a certain university research department or profiling some "learned body" or other) will finally get people talking, sharing and finding out/admitting that there has been a significant amount of over-caution in the mix...