So this post can possibly only really be answered by someone who actually made the game but here goes.
Question 1:
If for example, I block a player for whatever reason, does this game recognize the block and prevent me from being placed in the same instance of the world? I know some games don't recognize/integrate that part of Microsoft technology (I'm on xbox if that matters)
(I have a feeling this is kinda impossible to answer but just for fun.)
Question 2:
If the answer to question 1 is yes.
How many people would I theoretically have to block to have an instance to myself? If I blocked enough people is it actually possible to make this into a PvE game?
