Lordaeron BG trigger queue question

After doing about 20+ BGs (L70-79) over the last few days, I noticed the Alliance never outnumbered the Horde.

About 30% of the time, the BG started with equal numbers, and 70% of the time the Horde had from 1-2 more at startup. Today one even started 2 vs 6.
The Allliance never outnumbered the Horde in any of these BGs.

I watch numbers carefully during the BG, and they never balance ... the factions pretty much stay in the same unbalanced proportions/ratios.

I can understand this happening a few times in a row, but for it to happen consistently over a few days seems a bit odd. Does anyone know how this occurs? Is it because the Horde consistently join in a group? Can these BGs somehow be manufactured to be unbalanced?

For example, one faction can use another faction alt to simultaneously queue, but never join the BG. Then they just have to wait for one/few legit players to trigger the start?