I am more familiar with American tax law than Norwegian but I have huge doubts it’s illegal to have money offshore. Having money in more than one country is a pretty good hedge. When the Greek banks shut down and imposed atm restrictions, only Greeks with foreign bank accounts were able to access their money for example.

I’m searching but if you find anything on what constitutes ‘hiding’ in Norwegian tax law as it relates to offshore accounts it would be much appreciated.

I have a feeling ‘hiding’ is another one of those spirit of the law / unwritten societal rules sort of thing in this context.