Ischgl isn't a private business: its a municipality* and the reports suggest that the cover-up included the entire valley: Galtür, Mathon, Kappl, See, etc.
* Something that would have taken you < 5 seconds to confirm for yourself.
Hence this is the government, i.e. similar (but yes, not identical) to a regional or national state authority in your example.
So,
1. to reinforce you point: 'cover-ups are prevalent in authoritarian states'. Agreed
2. and to re-make my point: '… apparently also in stable, affluent, western democracies where information flows like wine'.
It would appear that your attachment to your hypothesis that authoritarian states get away with this kind of corruption because of their control over information is preventing you from assimilating new information that this kind of corruption can happen just as easily in free democratic states.
Which should worry you, if you do indeed live in such a state and are hoping that information freedom and democracy is enough to protect you and yours.