Combat logging and cross faction teaming

Anyone know the rules about this matter? for example engaging in combat pvp and the guy logs through another wow client to disconnect himself to avoid dying over and over again, and yes I'm pretty sure that it is the case considering whenever he's actually trying to kill me he never DCs, whenever he's dropping too low and trying to run away his character just disappears. And say a horde player has an alliance friend to clear out a farm area of other horde players so he himself can farm that alone.

Yea is cross fraction helping allowed?
Its pretty annoying and robbs the fun of gaming.
In Skettis is a Team Allyplayer and Hordplayer who plays together. Impossible to do smth about that.
Everybody has a limit of time to play.
Not fun at all playin like this.

There is nothing in the rules and conditions to prevent this.

Regarding factions:
Players are allowed to create characters on both factions.
Players are allowed to kill players of opposing faction of any level.
Players are allowed to have multiple accounts, and to play characters of both factions at the same time.
Players may associate with and solicit the help of players from the opposing faction.

Regarding PVP:
Players may exit the game at any time (Alt-F4 to escape pvp combat).
Players leaving a battleground for any reason prior to game end will receive a Deserter debuff (to disuade Alt-F4 exit during battlegrounds).

It is generally suggested that if you are being camped at a particular location by high level opposite faction players, then your best bet is to relocate and quest elsewhere for a time (20-30 minutes is usually long enough for gankers to get bored if no one is around to gank).