Lots of people are leveling alts using the Legion Invasion system....
1. Start picking off alts when they take some AoE damage from his rain of fire.
2. Gear 110s will attack you to defend the alts.
3. World PvP breaks out between geared 110s.
I actually started some today by zapping alts with my Overcharged Lightning Bolt on my 108 enhance shammy alt. For extra aggreavation I'm an engineer, so I got multiple outs like Spirit Walk, Lightning Surge totem, Nitro Boosts tinker and invis potions. I'm pretty hard to kill.