No national anthem at Mavs game

[Dahlsim]

At some point in the future, I hope we look back at the imaginary dividing lines between countries as dumb, even. But that's just me.

Certainly not just you. The idea of one big happy global community is very much on many minds and agendas. The question is how to get there. 

Even at the most elementary level, at your hypothetical point in the future, for lines to be dumb i.e. unimportant, you would need 

• No country to desire to do things differently than any other group. 
  
• No country to be willing to force by violence, deception, theft etc. its will on another country 
  

If one country wants to do things in significantly different way then it requires very real dividing lines of some kind to distinguish this group that's operating this way from that group operating another way. 
This gets into the entire idea of how a nation is defined for example. 

As for force, violence, deception, theft etc. as long as that exists the need for dividing lines remains a very real one.  Take for example border of a country.  

Should a country assume that if no borders are enforced then no one that comes into a territory has any intentions to do anything harmful to others in the region?  
If the lines are not needed, will everyone that enters a region be harmless to everyone else? 

How about your home/property?  Could the dividing lines be considered imaginary or are there real considerations for enforcing lines?