Isn't the whole Madeira thing very risky since it's based on "a relationship with the government"?

Unless Madeira separates from Portugal, it would have to obey all EU legislation which is increasingly draconian. However, both Madeira and Portugal are 70-80 Soc/SocDem and those guys won't even consider the separation.

Portugal's Socialist government has already introduced a stupid capital gains law. Does it affect Madeira? If not, what prevents Madeira from enacting the exact same law?