-even player count: horde will join within 20sec max
-ally joins, player count becomes even, within 20sec horde will join
-horde leaves, within 20sec new horde will join
Possible causes to this obvious unbalance:
-server auto-balances games and allows 1 horde extra and horde has more players in queue, but I have seen games where it is 5v6 and then a horde joins and it becomes 5v7 (this reason is unfair for alliance)
-insane randomness (very unlikely)
-devs hate alliance and make bot player join when the game becomes fair (

Please tell me what you think of this, and play a battleground and look at the player count if you don't believe this