> What exactly counts as "abuse"?

Nordic countries are higher-trust than America is, and so sometimes concepts like this do not need to be formally defined: "you know it when you see it" is a valid concept when people have sufficient dignity and respect for self and others as to not claim abuse when it's not actually present.

This breaks down in a system with different game-theoretical Schelling points - different "default strategies". If the default mode of behaviour for a large constituency of participants is to exploit all available weaknesses in the system, then the system has to become more formalized, more defensive, and eventually has to put firewalls around anything that could be exploited.

This is among the reasons why socialized medicine / welfare / etc work better in some countries than others. If it comes coupled with a high sense of dignity that makes one not want to fling oneself upon the commons unless it's strictly necessary, then it can do well; but if everyone wants to take everything that isn't nailed down, you simply cannot afford to offer as much, ever.