The problem is that thanks to the complexity of the tax systems and the interaction of international tax treaties the tax avoidance/tax evasion boundary is fuzzily defined and at the end of the day only a judge can decide on the legality.

So if a company, instead of staying well within the boundary decides to skirt it (and I'm sure that they take into account the probability of being caught on the wrong side in their minimization process), it is only fair that they get a visit from the tax man.