Mobbing vs. Capping in AB

Why is it in Alliance Battles, that the Kurzicks seem to try to cap and Luxons mob a majority of the time? Any ideas on why this happens?

It happens on both sides, both sides mob, both sides don't mob.

Kurzicks sometimes cap.
Kurzicks sometimes mob.
Luxon sometimes cap.
Luxon sometimes mob.

Both of them cap and mob. This thread is quite pointless seeing as there cannot be a real discussion, so I'm going to close it.