A detail that almost everyone overlooked: let us say that Feldmahler, instead of pulling the plug, decided to ignore the second C&D letter. In this case, the only option for Universal would have been suing him in Canada. They cannot really sue him in Austria as an Austrian court is not competent for an infringement done outside its territory - this unless Feldmahler were so stupid to sign the statement in the first C&D letter - this being a contract under Austrian law and under the competence of an Austrian court.
The clause stating that Canadian courts will enforce Austrian judgements is pure terrorism. Of course if you steal, say, 10000 euros in Vienna and you run away to Ottawa the Austrian court will rule against you and turn to Canadian judicial system for enforcement. But if you steal the same 10000 euros in Ottawa from a Viennese guy, the case will belong to a Canadian court - were the Viennese guy to raise the case in an Austrian court, the court would declare it outside of its competence.
If you read carefully, Mr. Clark does not rule out raising the case in a Canadian court - as the probabilities of winning the case in an European court are quite low.
Also, a general concept: publishers often threaten legal action, but rarely take the action in reality. Publishers - let alone classical music publishers - are not swimming in cash and a legal action is expensive even for them. Only actions where the outcome is reasonably clear are likely to be taken.
The more I read the C&D letters, the more they look absurd to me. I rest my opinion, had Universal asked quietly for the removal of some specific files, Feldmahler probably would have complied quietly. They have asked roughly and now they have a problem for their public relations department.
Of course nobody can really blame Feldmahler for not being willing to test the case himself.