It is likely that most of those getting leant on by the Stasi are already paying full tax in RoI. The squabble occurs because a number of countries all want to claim tax primacy over some poor contract pilot whose getting pulled in all directions - this is what needs to be resolved, and is not an indication of tax evasion.
There are still a few pilots out there on old, old contracts which pre-date RYR's mandatory tax compliance contract terms. For those guys, tax arrangements are their own responsibility, but all of those that I have met claimed to pay tax somewhere. A far cry from the 99% evasion alleged.
As 2W2R rightly said, its Friday evening... happy hour.