That's not necessarily true for either statement.
For Schoolyard - last time, those teams just imploded and died and players ended up getting shifted around. That's usually due to the captains picking the teams not knowing histories and putting two enemies together. SOMETIMES it ends up mending the relationship as both end up respecting each other more. Other times... well...
But teams are not set in stone once picked. But all captains must agree together to some extent on if switches can be made.
As for Factions. Don't forget, those people with long lists of contacts usually also have long lists of contacts that fight them as well. And if you recall, the last CE, Rania pulled out all the contacts and didn't win with them. The world literally came together to beat down a common enemy.