I've never really had a problem, I just join as party. Never really seen any premades, and if I do they still don't play well enough to win. I love battlegrounds because you rarely come across a team that works as well as arena teams do. It kinda makes me laugh that the only way to get a team of 5 people to actually work together is to squish them in where they can't escape. Even the BEM arena map is large enough to give many teams enough room to get spread out and disorganized.