I think the default is 2. I ran into this problem during college since I gave a couple friends my password. One day I was watching and it wouldn't play the next

I think the default is 2. I ran into this problem during college since I gave a couple friends my password. One day I was watching and it wouldn't play the next episode since there were 3 streams going at the same time, so I had to upgrade to the $11/4 streams plan. This policy goes back to 2012 IIRC.